St Thomas Weather Records (CA006137361)
Record envelope, standing records and threshold days for St Thomas (CA006137361), Ontario, Canada, with 99 years of record.
Key Facts for St Thomas
- St Thomas (CA006137361) is a weather station in Ontario, Canada at 42.78 latitude and -81.17 longitude, 236 m (774 ft) above sea level.
- The station reports from 1882 to 1980, 99 years of record.
- 1,464 records set at St Thomas still stand.
- Records are tracked for tmax, tmin, prcp, snow: an element needs 30 years of data to be eligible.
- St Thomas set a daily record low maximum temperature of 1.5 C (34.7 F) on 16 April 1980.
About the Station
- Location: Ontario, Canada, 42.78 latitude, -81.17 longitude.
- Elevation: 236 m (774 ft).
- Period of record: 1882 to 1980, 99 years.
- Eligible elements: tmax, tmin, prcp, snow.
Daily Record Envelope and 2026
0 days at or beyond a record| Month | Highest record high | Lowest record low | 2026 highest maximum | 2026 lowest minimum |
|---|---|---|---|---|
| Jan | 16.7 C (62.1 F) | -33.9 C (-29.0 F) | n/a | n/a |
| Feb | 16.1 C (61.0 F) | -34.4 C (-29.9 F) | n/a | n/a |
| Mar | 26.1 C (79.0 F) | -26.5 C (-15.7 F) | n/a | n/a |
| Apr | 29.4 C (84.9 F) | -12.8 C (9.0 F) | n/a | n/a |
| May | 32.2 C (90.0 F) | -5.6 C (21.9 F) | n/a | n/a |
| Jun | 35.6 C (96.1 F) | -2.2 C (28.0 F) | n/a | n/a |
| Jul | 38.9 C (102.0 F) | 3.3 C (37.9 F) | n/a | n/a |
| Aug | 36.1 C (97.0 F) | 1.7 C (35.1 F) | n/a | n/a |
| Sep | 35.6 C (96.1 F) | -2.8 C (27.0 F) | n/a | n/a |
| Oct | 30.0 C (86.0 F) | -8.3 C (17.1 F) | n/a | n/a |
| Nov | 23.3 C (73.9 F) | -17.8 C (0.0 F) | n/a | n/a |
| Dec | 17.2 C (63.0 F) | -30.6 C (-23.1 F) | n/a | n/a |
Which Years Hold Standing Records
1,464 standing records| Year set | Standing records |
|---|---|
| 1925 | 10 |
| 1926 | 39 |
| 1927 | 35 |
| 1928 | 34 |
| 1929 | 39 |
| 1930 | 35 |
| 1931 | 34 |
| 1932 | 29 |
| 1933 | 37 |
| 1934 | 54 |
| 1935 | 27 |
| 1936 | 42 |
| 1937 | 22 |
| 1938 | 28 |
| 1939 | 17 |
| 1940 | 26 |
| 1941 | 31 |
| 1942 | 29 |
| 1943 | 27 |
| 1944 | 22 |
| 1945 | 39 |
| 1946 | 32 |
| 1947 | 29 |
| 1948 | 15 |
| 1949 | 29 |
| 1950 | 21 |
| 1951 | 35 |
| 1952 | 15 |
| 1953 | 16 |
| 1954 | 23 |
| 1955 | 34 |
| 1956 | 25 |
| 1957 | 27 |
| 1958 | 12 |
| 1959 | 26 |
| 1960 | 16 |
| 1961 | 14 |
| 1962 | 28 |
| 1963 | 31 |
| 1964 | 19 |
| 1965 | 25 |
| 1966 | 24 |
| 1967 | 33 |
| 1968 | 17 |
| 1969 | 16 |
| 1970 | 22 |
| 1971 | 23 |
| 1972 | 21 |
| 1973 | 22 |
| 1974 | 18 |
| 1975 | 20 |
| 1976 | 24 |
| 1977 | 40 |
| 1978 | 16 |
| 1979 | 34 |
| 1980 | 6 |
All-Time Record Progression
5 new records| Date | Kind | Detail |
|---|---|---|
| 1954-03-29 | Record daily snowfall | Record daily snowfall 27.9 cm (11.0 in) |
| 1955-03-26 | Record daily snowfall | Record daily snowfall 29.2 cm (11.5 in) |
| 1964-08-22 | Record daily precipitation | Record daily precipitation 86.9 mm (3.4 in) |
| 1968-06-25 | Record daily precipitation | Record daily precipitation 104.6 mm (4.1 in) |
| 1978-01-26 | Record daily snowfall | Record daily snowfall 31.8 cm (12.5 in) |
Wettest Day of Each Month
Jun: 104.6 mm (4.1 in)| Month | Record daily precipitation (mm) | Date |
|---|---|---|
| Jan | 61.2 mm (2.4 in) | 13 January 1968 |
| Feb | 85.6 mm (3.4 in) | 19 February 1939 |
| Mar | 47.8 mm (1.9 in) | 12 March 1977 |
| Apr | 67.8 mm (2.7 in) | 26 April 1937 |
| May | 72.4 mm (2.9 in) | 26 May 1932 |
| Jun | 104.6 mm (4.1 in) | 25 June 1968 |
| Jul | 47.0 mm (1.9 in) | 31 July 1938 |
| Aug | 86.9 mm (3.4 in) | 22 August 1964 |
| Sep | 82.3 mm (3.2 in) | 23 September 1926 |
| Oct | 71.9 mm (2.8 in) | 1 October 1945 |
| Nov | 48.3 mm (1.9 in) | 27 November 1887 |
| Dec | 46.2 mm (1.8 in) | 21 December 1967 |
Period of Record Coverage
1925 to 1980| Year | Days with data | Share of year | Complete |
|---|---|---|---|
| 1925 | 92 | 25% | No |
| 1926 | 363 | 99% | Yes |
| 1927 | 364 | 100% | Yes |
| 1928 | 366 | 100% | Yes |
| 1929 | 365 | 100% | Yes |
| 1930 | 365 | 100% | Yes |
| 1931 | 364 | 100% | Yes |
| 1932 | 366 | 100% | Yes |
| 1933 | 365 | 100% | Yes |
| 1934 | 365 | 100% | Yes |
| 1935 | 365 | 100% | Yes |
| 1936 | 366 | 100% | Yes |
| 1937 | 365 | 100% | Yes |
| 1938 | 365 | 100% | Yes |
| 1939 | 365 | 100% | Yes |
| 1940 | 366 | 100% | Yes |
| 1941 | 365 | 100% | Yes |
| 1942 | 365 | 100% | Yes |
| 1943 | 365 | 100% | Yes |
| 1944 | 365 | 100% | Yes |
| 1945 | 365 | 100% | Yes |
| 1946 | 365 | 100% | Yes |
| 1947 | 365 | 100% | Yes |
| 1948 | 366 | 100% | Yes |
| 1949 | 365 | 100% | Yes |
| 1950 | 365 | 100% | Yes |
| 1951 | 365 | 100% | Yes |
| 1952 | 366 | 100% | Yes |
| 1953 | 365 | 100% | Yes |
| 1954 | 365 | 100% | Yes |
| 1955 | 365 | 100% | Yes |
| 1956 | 366 | 100% | Yes |
| 1957 | 365 | 100% | Yes |
| 1958 | 365 | 100% | Yes |
| 1959 | 365 | 100% | Yes |
| 1960 | 366 | 100% | Yes |
| 1961 | 365 | 100% | Yes |
| 1962 | 364 | 100% | Yes |
| 1963 | 365 | 100% | Yes |
| 1964 | 366 | 100% | Yes |
| 1965 | 365 | 100% | Yes |
| 1966 | 365 | 100% | Yes |
| 1967 | 365 | 100% | Yes |
| 1968 | 366 | 100% | Yes |
| 1969 | 365 | 100% | Yes |
| 1970 | 365 | 100% | Yes |
| 1971 | 361 | 99% | Yes |
| 1972 | 365 | 100% | Yes |
| 1973 | 365 | 100% | Yes |
| 1974 | 365 | 100% | Yes |
| 1975 | 365 | 100% | Yes |
| 1976 | 366 | 100% | Yes |
| 1977 | 365 | 100% | Yes |
| 1978 | 365 | 100% | Yes |
| 1979 | 347 | 95% | Yes |
| 1980 | 73 | 20% | No |
Latest Records
20| Date | Station | Record | Value | Beat old record by | Old record stood | Significance |
|---|---|---|---|---|---|---|
| 16 April 1980 | St Thomas, CA | daily low max | 1.5 C (34.7 F) | 1.3 C (2.3 F) | 52 years | 22 of 100 (Routine) |
| 14 April 1980 | St Thomas, CA | daily rain | 26.2 mm (1.0 in) | 0.8 mm (0.03 in) | 88 years | 35 of 100 (Notable) |
| 9 April 1980 | St Thomas, CA | daily high min | 6.5 C (43.7 F) | 1.5 C (2.7 F) | 29 years | 16 of 100 (Routine) |
| 8 April 1980 | St Thomas, CA | daily high min | 9.0 C (48.2 F) | 1.8 C (3.2 F) | 51 years | 23 of 100 (Routine) |
| 20 March 1980 | St Thomas, CA | daily rain | 28.2 mm (1.1 in) | 6.0 mm (0.24 in) | 2 years | 18 of 100 (Routine) |
| 29 February 1980 | St Thomas, CA | daily low max | -8.0 C (17.6 F) | 4.7 C (8.5 F) | 20 years | 19 of 100 (Routine) |
| 29 February 1980 | St Thomas, CA | daily low min | -21.5 C (-6.7 F) | 4.3 C (7.7 F) | 20 years | 17 of 100 (Routine) |
| 28 February 1980 | St Thomas, CA | daily low max | -8.5 C (16.7 F) | 2.9 C (5.2 F) | 38 years | 21 of 100 (Routine) |
| 10 January 1980 | St Thomas, CA | daily rain | 27.0 mm (1.1 in) | 4.1 mm (0.16 in) | 86 years | 41 of 100 (Notable) |
| 11 December 1979 | St Thomas, CA | daily high min | 4.0 C (39.2 F) | 1.8 C (3.2 F) | 8 years | 9 of 100 (Routine) |
| 26 November 1979 | St Thomas, CA | daily high max | 14.0 C (57.2 F) | 1.2 C (2.2 F) | 26 years | 15 of 100 (Routine) |
| 25 November 1979 | St Thomas, CA | daily high max | 14.0 C (57.2 F) | 0.1 C (0.2 F) | 32 years | 14 of 100 (Routine) |
| 23 November 1979 | St Thomas, CA | daily high min | 10.0 C (50.0 F) | 1.7 C (3.1 F) | 48 years | 22 of 100 (Routine) |
| 22 November 1979 | St Thomas, CA | daily rain | 33.8 mm (1.3 in) | 15.3 mm (0.6 in) | 95 years | 57 of 100 (Notable) |
| 26 October 1979 | St Thomas, CA | daily low max | 2.5 C (36.5 F) | 0.8 C (1.4 F) | 16 years | 11 of 100 (Routine) |
| 25 October 1979 | St Thomas, CA | daily low max | 3.5 C (38.3 F) | 0.4 C (0.7 F) | 16 years | 10 of 100 (Routine) |
| 22 October 1979 | St Thomas, CA | daily high min | 17.5 C (63.5 F) | 5.3 C (9.5 F) | 49 years | 29 of 100 (Routine) |
| 21 October 1979 | St Thomas, CA | daily high min | 17.0 C (62.6 F) | 1.4 C (2.5 F) | 42 years | 19 of 100 (Routine) |
| 20 October 1979 | St Thomas, CA | daily high min | 15.0 C (59.0 F) | 3.9 C (7.0 F) | 16 years | 17 of 100 (Routine) |
| 11 October 1979 | St Thomas, CA | daily low min | -3.0 C (26.6 F) | 0.2 C (0.4 F) | 22 years | 11 of 100 (Routine) |
Climate Trend
53 complete years, 1926 to 1978| Year | Annual mean temperature | Difference from the station mean |
|---|---|---|
| 1926 | 6.5 C | -1.35 C |
| 1927 | 8.0 C | +0.15 C |
| 1928 | 7.6 C | -0.19 C |
| 1929 | 7.1 C | -0.75 C |
| 1930 | 7.7 C | -0.14 C |
| 1931 | 9.2 C | +1.37 C |
| 1932 | 8.2 C | +0.41 C |
| 1933 | 8.5 C | +0.67 C |
| 1934 | 7.3 C | -0.49 C |
| 1935 | 7.2 C | -0.63 C |
| 1936 | 7.5 C | -0.37 C |
| 1937 | 8.0 C | +0.17 C |
| 1938 | 8.8 C | +0.96 C |
| 1939 | 8.4 C | +0.54 C |
| 1940 | 7.0 C | -0.78 C |
| 1941 | 8.9 C | +1.11 C |
| 1942 | 8.3 C | +0.48 C |
| 1943 | 7.4 C | -0.46 C |
| 1944 | 8.3 C | +0.47 C |
| 1945 | 7.7 C | -0.12 C |
| 1946 | 9.0 C | +1.15 C |
| 1947 | 8.1 C | +0.24 C |
| 1948 | 8.0 C | +0.21 C |
| 1949 | 9.2 C | +1.40 C |
| 1950 | 7.5 C | -0.30 C |
| 1951 | 7.7 C | -0.15 C |
| 1952 | 8.5 C | +0.64 C |
| 1953 | 8.9 C | +1.10 C |
| 1954 | 8.1 C | +0.25 C |
| 1955 | 8.8 C | +0.98 C |
| 1956 | 7.7 C | -0.08 C |
| 1957 | 7.9 C | +0.12 C |
| 1958 | 7.2 C | -0.61 C |
| 1959 | 8.1 C | +0.32 C |
| 1960 | 7.4 C | -0.40 C |
| 1961 | 8.1 C | +0.23 C |
| 1962 | 7.4 C | -0.38 C |
| 1963 | 6.8 C | -0.99 C |
| 1964 | 7.9 C | +0.08 C |
| 1965 | 7.4 C | -0.42 C |
| 1966 | 7.0 C | -0.87 C |
| 1967 | 6.9 C | -0.90 C |
| 1968 | 7.4 C | -0.46 C |
| 1969 | 7.5 C | -0.35 C |
| 1970 | 7.5 C | -0.30 C |
| 1971 | 8.0 C | +0.18 C |
| 1972 | 6.9 C | -0.94 C |
| 1973 | 8.8 C | +0.95 C |
| 1974 | 7.5 C | -0.29 C |
| 1975 | 8.3 C | +0.52 C |
| 1976 | 7.1 C | -0.68 C |
| 1977 | 7.9 C | +0.05 C |
| 1978 | 6.7 C | -1.17 C |
The fitted trend in annual mean temperature here over 1926 to 1978 is -0.09 C (-0.21 to 0.03) per decade. The interval includes zero, so the trend is not clearly different from zero. In Fahrenheit: -0.2 F (-0.4 to 0.1) per decade. The slope is a straight line fitted to 53 complete years; the brackets give its 95 percent interval.
| Measure | Per decade (C) | Per decade (F) | Period | Complete years | Reading |
|---|---|---|---|---|---|
| Annual mean temperature | -0.09 C (-0.21 to 0.03) per decade | -0.2 F (-0.4 to 0.1) per decade | 1926 to 1978 | 53 | Not clearly different from zero |
| Mean daily maximum | -0.3 C (-0.4 to -0.2) per decade | -0.6 F (-0.8 to -0.3) per decade | 1926 to 1978 | 53 | Fall |
| Mean daily minimum | 0.14 C (0.01 to 0.27) per decade | 0.25 F (0.02 to 0.48) per decade | 1926 to 1978 | 53 | Rise |
A year is complete when all 12 months have at least 20 days of both daily maximum and daily minimum readings. The annual mean is the mean of the monthly means. The trend describes this one station over this period; it does not say what caused the change.
Extremes by Year
1882 to 1980| Measure | Record | Year of the record | Median year | Years with a value |
|---|---|---|---|---|
| Hottest day (TXx) | 38.9 C (102.0 F) | 1936 | 33.1 C (91.5 F) | 56 |
| Coldest night (TNn) | -34.4 C (-29.9 F) | 1929 | -25.5 C (-14.0 F) | 56 |
| Wettest day (Rx1day) | 104.6 mm (4.1 in) | 1968 | 44.1 mm (1.7 in) | 68 |
| Wettest five days (Rx5day) | 122.8 mm (4.8 in) | 1954 | 66.1 mm (2.6 in) | 68 |
| Longest dry spell (CDD) | 32 days | 1943 | 17 days | 68 |
Hottest day (TXx)
| Year | Hottest day (TXx) |
|---|---|
| 1882 | n/a |
| 1883 | n/a |
| 1884 | n/a |
| 1885 | n/a |
| 1886 | n/a |
| 1887 | n/a |
| 1888 | n/a |
| 1890 | n/a |
| 1891 | n/a |
| 1892 | n/a |
| 1893 | n/a |
| 1894 | n/a |
| 1895 | n/a |
| 1925 | 20.0 C (68.0 F) |
| 1926 | 36.7 C (98.1 F) |
| 1927 | 33.3 C (91.9 F) |
| 1928 | 31.7 C (89.1 F) |
| 1929 | 32.8 C (91.0 F) |
| 1930 | 36.1 C (97.0 F) |
| 1931 | 36.1 C (97.0 F) |
| 1932 | 33.3 C (91.9 F) |
| 1933 | 36.1 C (97.0 F) |
| 1934 | 35.0 C (95.0 F) |
| 1935 | 33.3 C (91.9 F) |
| 1936 | 38.9 C (102.0 F) |
| 1937 | 33.3 C (91.9 F) |
| 1938 | 31.1 C (88.0 F) |
| 1939 | 33.3 C (91.9 F) |
| 1940 | 33.3 C (91.9 F) |
| 1941 | 35.0 C (95.0 F) |
| 1942 | 35.0 C (95.0 F) |
| 1943 | 32.8 C (91.0 F) |
| 1944 | 33.3 C (91.9 F) |
| 1945 | 32.8 C (91.0 F) |
| 1946 | 31.7 C (89.1 F) |
| 1947 | 33.3 C (91.9 F) |
| 1948 | 35.0 C (95.0 F) |
| 1949 | 36.7 C (98.1 F) |
| 1950 | 30.6 C (87.1 F) |
| 1951 | 30.6 C (87.1 F) |
| 1952 | 35.6 C (96.1 F) |
| 1953 | 35.6 C (96.1 F) |
| 1954 | 35.0 C (95.0 F) |
| 1955 | 37.2 C (99.0 F) |
| 1956 | 32.8 C (91.0 F) |
| 1957 | 32.8 C (91.0 F) |
| 1958 | 31.1 C (88.0 F) |
| 1959 | 32.8 C (91.0 F) |
| 1960 | 31.1 C (88.0 F) |
| 1961 | 31.1 C (88.0 F) |
| 1962 | 32.2 C (90.0 F) |
| 1963 | 31.7 C (89.1 F) |
| 1964 | 33.3 C (91.9 F) |
| 1965 | 32.2 C (90.0 F) |
| 1966 | 35.0 C (95.0 F) |
| 1967 | 31.1 C (88.0 F) |
| 1968 | 32.8 C (91.0 F) |
| 1969 | 31.7 C (89.1 F) |
| 1970 | 31.1 C (88.0 F) |
| 1971 | 34.4 C (93.9 F) |
| 1972 | 31.1 C (88.0 F) |
| 1973 | 33.3 C (91.9 F) |
| 1974 | 32.2 C (90.0 F) |
| 1975 | 33.9 C (93.0 F) |
| 1976 | 31.1 C (88.0 F) |
| 1977 | 35.0 C (95.0 F) |
| 1978 | 32.5 C (90.5 F) |
| 1979 | 31.0 C (87.8 F) |
| 1980 | 19.0 C (66.2 F) |
Coldest night (TNn)
| Year | Coldest night (TNn) |
|---|---|
| 1882 | n/a |
| 1883 | n/a |
| 1884 | n/a |
| 1885 | n/a |
| 1886 | n/a |
| 1887 | n/a |
| 1888 | n/a |
| 1890 | n/a |
| 1891 | n/a |
| 1892 | n/a |
| 1893 | n/a |
| 1894 | n/a |
| 1895 | n/a |
| 1925 | -23.3 C (-9.9 F) |
| 1926 | -26.7 C (-16.1 F) |
| 1927 | -30.6 C (-23.1 F) |
| 1928 | -32.2 C (-26.0 F) |
| 1929 | -34.4 C (-29.9 F) |
| 1930 | -26.1 C (-15.0 F) |
| 1931 | -17.8 C (0.0 F) |
| 1932 | -18.3 C (-0.9 F) |
| 1933 | -23.3 C (-9.9 F) |
| 1934 | -32.8 C (-27.0 F) |
| 1935 | -26.7 C (-16.1 F) |
| 1936 | -29.4 C (-20.9 F) |
| 1937 | -21.1 C (-6.0 F) |
| 1938 | -20.6 C (-5.1 F) |
| 1939 | -21.1 C (-6.0 F) |
| 1940 | -26.7 C (-16.1 F) |
| 1941 | -19.4 C (-2.9 F) |
| 1942 | -25.6 C (-14.1 F) |
| 1943 | -26.7 C (-16.1 F) |
| 1944 | -29.4 C (-20.9 F) |
| 1945 | -28.9 C (-20.0 F) |
| 1946 | -19.4 C (-2.9 F) |
| 1947 | -17.2 C (1.0 F) |
| 1948 | -30.0 C (-22.0 F) |
| 1949 | -18.9 C (-2.0 F) |
| 1950 | -21.1 C (-6.0 F) |
| 1951 | -26.1 C (-15.0 F) |
| 1952 | -17.2 C (1.0 F) |
| 1953 | -21.1 C (-6.0 F) |
| 1954 | -26.7 C (-16.1 F) |
| 1955 | -27.8 C (-18.0 F) |
| 1956 | -18.3 C (-0.9 F) |
| 1957 | -27.8 C (-18.0 F) |
| 1958 | -23.3 C (-9.9 F) |
| 1959 | -27.8 C (-18.0 F) |
| 1960 | -22.2 C (-8.0 F) |
| 1961 | -30.6 C (-23.1 F) |
| 1962 | -30.6 C (-23.1 F) |
| 1963 | -30.0 C (-22.0 F) |
| 1964 | -23.3 C (-9.9 F) |
| 1965 | -23.3 C (-9.9 F) |
| 1966 | -26.7 C (-16.1 F) |
| 1967 | -26.7 C (-16.1 F) |
| 1968 | -24.4 C (-11.9 F) |
| 1969 | -20.0 C (-4.0 F) |
| 1970 | -33.9 C (-29.0 F) |
| 1971 | -24.4 C (-11.9 F) |
| 1972 | -26.1 C (-15.0 F) |
| 1973 | -23.3 C (-9.9 F) |
| 1974 | -20.6 C (-5.1 F) |
| 1975 | -23.3 C (-9.9 F) |
| 1976 | -32.8 C (-27.0 F) |
| 1977 | -24.4 C (-11.9 F) |
| 1978 | -29.0 C (-20.2 F) |
| 1979 | -25.5 C (-13.9 F) |
| 1980 | -21.5 C (-6.7 F) |
Wettest day (Rx1day)
| Year | Wettest day (Rx1day) |
|---|---|
| 1882 | 50.5 mm (2.0 in) |
| 1883 | 43.7 mm (1.7 in) |
| 1884 | 32.5 mm (1.3 in) |
| 1885 | 54.6 mm (2.1 in) |
| 1886 | 44.5 mm (1.8 in) |
| 1887 | 48.3 mm (1.9 in) |
| 1888 | n/a |
| 1890 | 63.5 mm (2.5 in) |
| 1891 | 52.8 mm (2.1 in) |
| 1892 | 49.8 mm (2.0 in) |
| 1893 | 25.4 mm (1.0 in) |
| 1894 | 47.5 mm (1.9 in) |
| 1895 | 14.0 mm (0.6 in) |
| 1925 | 34.3 mm (1.4 in) |
| 1926 | 82.3 mm (3.2 in) |
| 1927 | 56.6 mm (2.2 in) |
| 1928 | 62.2 mm (2.4 in) |
| 1929 | 39.6 mm (1.6 in) |
| 1930 | 50.3 mm (2.0 in) |
| 1931 | 37.6 mm (1.5 in) |
| 1932 | 72.4 mm (2.9 in) |
| 1933 | 28.7 mm (1.1 in) |
| 1934 | 26.2 mm (1.0 in) |
| 1935 | 63.2 mm (2.5 in) |
| 1936 | 32.8 mm (1.3 in) |
| 1937 | 67.8 mm (2.7 in) |
| 1938 | 56.4 mm (2.2 in) |
| 1939 | 85.6 mm (3.4 in) |
| 1940 | 56.9 mm (2.2 in) |
| 1941 | 26.7 mm (1.1 in) |
| 1942 | 53.8 mm (2.1 in) |
| 1943 | 35.6 mm (1.4 in) |
| 1944 | 33.5 mm (1.3 in) |
| 1945 | 71.9 mm (2.8 in) |
| 1946 | 40.1 mm (1.6 in) |
| 1947 | 55.4 mm (2.2 in) |
| 1948 | 29.5 mm (1.2 in) |
| 1949 | 35.1 mm (1.4 in) |
| 1950 | 32.3 mm (1.3 in) |
| 1951 | 33.8 mm (1.3 in) |
| 1952 | 45.0 mm (1.8 in) |
| 1953 | 33.0 mm (1.3 in) |
| 1954 | 50.0 mm (2.0 in) |
| 1955 | 54.1 mm (2.1 in) |
| 1956 | 60.7 mm (2.4 in) |
| 1957 | 42.7 mm (1.7 in) |
| 1958 | 36.3 mm (1.4 in) |
| 1959 | 35.8 mm (1.4 in) |
| 1960 | 38.6 mm (1.5 in) |
| 1961 | 31.8 mm (1.3 in) |
| 1962 | 42.2 mm (1.7 in) |
| 1963 | 29.7 mm (1.2 in) |
| 1964 | 86.9 mm (3.4 in) |
| 1965 | 50.0 mm (2.0 in) |
| 1966 | 37.1 mm (1.5 in) |
| 1967 | 78.5 mm (3.1 in) |
| 1968 | 104.6 mm (4.1 in) |
| 1969 | 52.1 mm (2.1 in) |
| 1970 | 33.0 mm (1.3 in) |
| 1971 | 30.2 mm (1.2 in) |
| 1972 | 40.4 mm (1.6 in) |
| 1973 | 32.8 mm (1.3 in) |
| 1974 | 27.2 mm (1.1 in) |
| 1975 | 66.0 mm (2.6 in) |
| 1976 | 56.1 mm (2.2 in) |
| 1977 | 50.5 mm (2.0 in) |
| 1978 | 33.4 mm (1.3 in) |
| 1979 | 55.4 mm (2.2 in) |
| 1980 | 28.2 mm (1.1 in) |
Wettest five days (Rx5day)
| Year | Wettest five days (Rx5day) |
|---|---|
| 1882 | 62.4 mm (2.5 in) |
| 1883 | 62.0 mm (2.4 in) |
| 1884 | 57.5 mm (2.3 in) |
| 1885 | 71.3 mm (2.8 in) |
| 1886 | 57.2 mm (2.3 in) |
| 1887 | 63.5 mm (2.5 in) |
| 1888 | n/a |
| 1890 | 68.9 mm (2.7 in) |
| 1891 | 70.1 mm (2.8 in) |
| 1892 | 65.5 mm (2.6 in) |
| 1893 | 44.8 mm (1.8 in) |
| 1894 | 94.8 mm (3.7 in) |
| 1895 | 21.1 mm (0.8 in) |
| 1925 | 42.5 mm (1.7 in) |
| 1926 | 82.3 mm (3.2 in) |
| 1927 | 86.3 mm (3.4 in) |
| 1928 | 71.6 mm (2.8 in) |
| 1929 | 68.3 mm (2.7 in) |
| 1930 | 62.2 mm (2.4 in) |
| 1931 | 61.0 mm (2.4 in) |
| 1932 | 75.5 mm (3.0 in) |
| 1933 | 32.3 mm (1.3 in) |
| 1934 | 40.4 mm (1.6 in) |
| 1935 | 68.0 mm (2.7 in) |
| 1936 | 50.8 mm (2.0 in) |
| 1937 | 111.5 mm (4.4 in) |
| 1938 | 65.0 mm (2.6 in) |
| 1939 | 98.3 mm (3.9 in) |
| 1940 | 65.6 mm (2.6 in) |
| 1941 | 35.8 mm (1.4 in) |
| 1942 | 70.7 mm (2.8 in) |
| 1943 | 51.6 mm (2.0 in) |
| 1944 | 51.8 mm (2.0 in) |
| 1945 | 91.7 mm (3.6 in) |
| 1946 | 66.6 mm (2.6 in) |
| 1947 | 74.2 mm (2.9 in) |
| 1948 | 56.9 mm (2.2 in) |
| 1949 | 48.5 mm (1.9 in) |
| 1950 | 75.9 mm (3.0 in) |
| 1951 | 44.7 mm (1.8 in) |
| 1952 | 90.0 mm (3.5 in) |
| 1953 | 58.0 mm (2.3 in) |
| 1954 | 122.8 mm (4.8 in) |
| 1955 | 66.6 mm (2.6 in) |
| 1956 | 61.7 mm (2.4 in) |
| 1957 | 56.0 mm (2.2 in) |
| 1958 | 64.3 mm (2.5 in) |
| 1959 | 55.9 mm (2.2 in) |
| 1960 | 88.1 mm (3.5 in) |
| 1961 | 61.8 mm (2.4 in) |
| 1962 | 51.6 mm (2.0 in) |
| 1963 | 54.0 mm (2.1 in) |
| 1964 | 119.4 mm (4.7 in) |
| 1965 | 68.7 mm (2.7 in) |
| 1966 | 88.9 mm (3.5 in) |
| 1967 | 86.8 mm (3.4 in) |
| 1968 | 114.2 mm (4.5 in) |
| 1969 | 80.9 mm (3.2 in) |
| 1970 | 54.4 mm (2.1 in) |
| 1971 | 47.0 mm (1.9 in) |
| 1972 | 66.5 mm (2.6 in) |
| 1973 | 69.1 mm (2.7 in) |
| 1974 | 59.2 mm (2.3 in) |
| 1975 | 109.2 mm (4.3 in) |
| 1976 | 82.5 mm (3.2 in) |
| 1977 | 92.0 mm (3.6 in) |
| 1978 | 67.8 mm (2.7 in) |
| 1979 | 86.8 mm (3.4 in) |
| 1980 | 47.2 mm (1.9 in) |
Longest dry spell (CDD)
| Year | Longest dry spell (CDD) |
|---|---|
| 1882 | 16 days |
| 1883 | 19 days |
| 1884 | 17 days |
| 1885 | 19 days |
| 1886 | 17 days |
| 1887 | 17 days |
| 1888 | n/a |
| 1890 | 21 days |
| 1891 | 16 days |
| 1892 | 10 days |
| 1893 | 11 days |
| 1894 | 9 days |
| 1895 | 18 days |
| 1925 | 12 days |
| 1926 | 18 days |
| 1927 | 16 days |
| 1928 | 13 days |
| 1929 | 17 days |
| 1930 | 19 days |
| 1931 | 17 days |
| 1932 | 14 days |
| 1933 | 19 days |
| 1934 | 20 days |
| 1935 | 17 days |
| 1936 | 21 days |
| 1937 | 13 days |
| 1938 | 11 days |
| 1939 | 14 days |
| 1940 | 11 days |
| 1941 | 14 days |
| 1942 | 21 days |
| 1943 | 32 days |
| 1944 | 19 days |
| 1945 | 10 days |
| 1946 | 12 days |
| 1947 | 18 days |
| 1948 | 18 days |
| 1949 | 19 days |
| 1950 | 13 days |
| 1951 | 12 days |
| 1952 | 16 days |
| 1953 | 24 days |
| 1954 | 13 days |
| 1955 | 21 days |
| 1956 | 16 days |
| 1957 | 22 days |
| 1958 | 20 days |
| 1959 | 19 days |
| 1960 | 13 days |
| 1961 | 17 days |
| 1962 | 13 days |
| 1963 | 26 days |
| 1964 | 20 days |
| 1965 | 14 days |
| 1966 | 18 days |
| 1967 | 25 days |
| 1968 | 13 days |
| 1969 | 18 days |
| 1970 | 18 days |
| 1971 | 17 days |
| 1972 | 13 days |
| 1973 | 27 days |
| 1974 | 16 days |
| 1975 | 15 days |
| 1976 | 19 days |
| 1977 | 10 days |
| 1978 | 25 days |
| 1979 | 16 days |
| 1980 | 8 days |
Each chart shows one value per year; the dot marks the record year. TXx is the hottest daily maximum, TNn the coldest daily minimum, Rx1day and Rx5day the largest one-day and five-day rain totals, and CDD the longest run of days with less than 1 mm of rain. A year with missing days can understate an extreme.
Frost Dates and Growing Season
53 years with a frostAcross 53 years with a frost, the median last spring frost at St Thomas falls on 14 May and the median first autumn frost on 3 October, which leaves a median of 140 days between them.
Fitted over all years, the growing season changes by +3.0 days per decade at this station.
| Measure | Median, all years | Earliest period | Recent period (1949 to 1978) | Recent against earliest | Fitted trend |
|---|---|---|---|---|---|
| Last spring frost | 14 May | n/a | 14 May | n/a | -1.9 days per decade |
| First autumn frost | 3 October | n/a | 4 October | n/a | +1.1 days per decade |
| Growing days | 140 days | n/a | 143 days | n/a | +3.0 days per decade |
A frost day is a day with a daily minimum at or below 0 C (32 F). The last spring frost and the first autumn frost are the last and first such days of the cold season, and growing days are the days between them. A negative trend for the last spring frost means it comes earlier.
Rainfall Return Levels
60 years, 1883 to 1979A day with at least 44.7 mm (1.8 in) of rain is expected about once in 2 years. A day with at least 109.4 mm (4.3 in) of rain is expected about once in 100 years.
| Expected about once in | A day with at least | Note |
|---|---|---|
| 2 years | 44.7 mm (1.8 in) | |
| 5 years | 60.3 mm (2.4 in) | |
| 10 years | 71.2 mm (2.8 in) | |
| 25 years | 85.9 mm (3.4 in) | |
| 50 years | 97.4 mm (3.8 in) | |
| 100 years | 109.4 mm (4.3 in) | Longer than the 60 years of record |
The levels come from a generalised extreme value (GEV) distribution fitted by L-moments to the wettest-day total of each year, 60 years of values from 1883 to 1979.
A return level is an estimate. It is least reliable for the long periods, 50 and 100 years, and for any period longer than the record behind the fit, where the fit has to reach past the largest day actually observed. It is not a forecast.
The largest wettest-day totals in the fit: 104.6 mm (4.1 in) in 1968; 86.9 mm (3.4 in) in 1964; 85.6 mm (3.4 in) in 1939.
Station Changes
3 suspected3 changes were suspected in the annual mean temperature of St Thomas, at 1941, 1951 and 1974. Each is measured against neighbouring stations.
- Relative to 5 neighbouring stations, the station's annual mean temperature from 1941 ran 0.2 C (0.3 F) higher than in the years before (likely change).
- Relative to 5 neighbouring stations, the station's annual mean temperature from 1951 ran 0.3 C (0.5 F) lower than in the years before (likely change).
- Relative to 5 neighbouring stations, the station's annual mean temperature from 1974 ran 0.2 C (0.4 F) higher than in the years before (possible change).
| Year | Shift (C) | Shift (F) | Strength | Neighbours |
|---|---|---|---|---|
| 1941 | +0.2 | +0.3 | likely | 5 |
| 1951 | -0.3 | -0.5 | likely | 5 |
| 1974 | +0.2 | +0.4 | possible | 5 |
Possible change at the station (a move, a new instrument or a new site); the record is kept as measured. A "likely" change has a larger test statistic than a "possible" one. Neither says why the station differs from its neighbours. How changes are found, and the largest ones.
Download the Data
Source: NOAA National Centers for Environmental Information, Global Historical Climatology Network Daily (GHCN-Daily). Records are computed by World Extreme Weather Monitor and are not official NOAA products. (US Government open data (NOAA NCEI)) Data as of 2026-10-17 (17 October 2026). Records are computed by this site and are not official.
Data as of . Last revised (2026-10-17).