Semans Threshold Days by Year (CA004017320)
19 fixed thresholds counted per year at Semans (CA004017320): hot days, frost, tropical nights and heavy rain, with the most days in a year.
Key Facts for Semans Thresholds
- Semans: nights with a minimum temperature at or below 0 C (32 F) in 51 years, most in 1935 with 253.
- Semans: nights with a minimum temperature at or below -10 C (14 F) in 51 years, most in 1935 with 151.
- Semans: nights with a minimum temperature at or below -20 C (-4 F) in 51 years, most in 1950 with 89.
- Semans: nights with a minimum temperature at or below -30 C (-22 F) in 50 years, most in 1972 with 44.
- 19 fixed thresholds have at least one qualifying day at Semans.
Days at or above 30 C (86 F)
47 years with a qualifying day| Year | Days | Decade average |
|---|---|---|
| 1924 | 6 | 12.3 |
| 1925 | 17 | 12.3 |
| 1927 | 7 | 12.3 |
| 1929 | 19 | 12.3 |
| 1930 | 27 | 33.7 |
| 1931 | 44 | 33.7 |
| 1939 | 30 | 33.7 |
| 1940 | 26 | 21.8 |
| 1941 | 29 | 21.8 |
| 1942 | 11 | 21.8 |
| 1943 | 20 | 21.8 |
| 1944 | 15 | 21.8 |
| 1945 | 22 | 21.8 |
| 1946 | 23 | 21.8 |
| 1947 | 28 | 21.8 |
| 1948 | 21 | 21.8 |
| 1949 | 23 | 21.8 |
| 1950 | 16 | 10 |
| 1951 | 7 | 10 |
| 1952 | 10 | 10 |
| 1953 | 5 | 10 |
| 1954 | 1 | 10 |
| 1955 | 13 | 10 |
| 1956 | 6 | 10 |
| 1957 | 14 | 10 |
| 1958 | 14 | 10 |
| 1959 | 14 | 10 |
| 1960 | 21 | 13.5 |
| 1965 | 6 | 13.5 |
| 1966 | 12 | 13.5 |
| 1967 | 22 | 13.5 |
| 1968 | 5 | 13.5 |
| 1969 | 15 | 13.5 |
| 1970 | 17 | 13 |
| 1971 | 13 | 13 |
| 1972 | 17 | 13 |
| 1973 | 9 | 13 |
| 1974 | 10 | 13 |
| 1975 | 13 | 13 |
| 1976 | 8 | 13 |
| 1977 | 9 | 13 |
| 1978 | 14 | 13 |
| 1979 | 20 | 13 |
| 1980 | 16 | 13.3 |
| 1981 | 15 | 13.3 |
| 1982 | 6 | 13.3 |
| 1983 | 16 | 13.3 |
| Year | First date | Last date |
|---|---|---|
| 1924 | 1924-07-04 | 1924-07-25 |
| 1925 | 1925-05-19 | 1925-09-03 |
| 1927 | 1927-06-26 | 1927-09-07 |
| 1929 | 1929-06-09 | 1929-08-31 |
| 1930 | 1930-05-03 | 1930-09-06 |
| 1931 | 1931-05-14 | 1931-09-07 |
| 1939 | 1939-05-29 | 1939-08-29 |
| 1940 | 1940-05-11 | 1940-09-04 |
| 1941 | 1941-06-16 | 1941-09-18 |
| 1942 | 1942-05-24 | 1942-09-10 |
| 1943 | 1943-07-04 | 1943-10-05 |
| 1944 | 1944-05-27 | 1944-08-08 |
| 1945 | 1945-06-21 | 1945-10-15 |
| 1946 | 1946-05-26 | 1946-09-15 |
| 1947 | 1947-07-02 | 1947-08-15 |
| 1948 | 1948-05-18 | 1948-09-22 |
| 1949 | 1949-04-28 | 1949-08-22 |
| 1950 | 1950-05-27 | 1950-09-25 |
| 1951 | 1951-05-23 | 1951-08-22 |
| 1952 | 1952-04-28 | 1952-08-25 |
| 1953 | 1953-07-10 | 1953-08-20 |
| 1954 | 1954-07-20 | 1954-07-20 |
| 1955 | 1955-06-29 | 1955-09-02 |
| 1956 | 1956-06-01 | 1956-09-26 |
| 1957 | 1957-07-09 | 1957-09-07 |
| 1958 | 1958-05-12 | 1958-08-17 |
| 1959 | 1959-06-05 | 1959-08-07 |
| 1960 | 1960-05-12 | 1960-09-04 |
| 1965 | 1965-06-10 | 1965-08-23 |
| 1966 | 1966-06-28 | 1966-09-11 |
| 1967 | 1967-06-26 | 1967-09-06 |
| 1968 | 1968-06-19 | 1968-09-11 |
| 1969 | 1969-05-26 | 1969-09-13 |
| 1970 | 1970-06-03 | 1970-08-24 |
| 1971 | 1971-05-13 | 1971-09-11 |
| 1972 | 1972-05-31 | 1972-08-29 |
| 1973 | 1973-06-23 | 1973-08-30 |
| 1974 | 1974-06-19 | 1974-08-06 |
| 1975 | 1975-06-24 | 1975-08-28 |
| 1976 | 1976-07-24 | 1976-09-06 |
| 1977 | 1977-05-10 | 1977-07-22 |
| 1978 | 1978-05-15 | 1978-09-04 |
| 1979 | 1979-06-12 | 1979-09-16 |
| 1980 | 1980-04-20 | 1980-09-07 |
| 1981 | 1981-05-21 | 1981-09-18 |
| 1982 | 1982-06-22 | 1982-09-08 |
| 1983 | 1983-06-24 | 1983-09-01 |
Every Fixed Threshold
| Threshold | Years with a qualifying day | Most days in a year | Year | Latest year days |
|---|---|---|---|---|
| 30 C (86 F): Days | 47 | 44 | 1931 | 16 |
| 35 C (95 F): Days | 30 | 11 | 1931 | 3 |
| 40 C (104 F): Days | 4 | 1 | 1931 | 1 |
| 90 F (32.2 C): Days | 43 | 22 | 1931 | 7 |
| 100 F (37.8 C): Days | 8 | 4 | 1931 | 1 |
| 0 C (32 F): Ice days (max | 47 | 153 | 1951 | 124 |
| 0 C (32 F): Frost days (min | 51 | 253 | 1935 | 207 |
| -10 C (14 F): Days with min | 51 | 151 | 1935 | 105 |
| -20 C (-4 F): Days with min | 51 | 89 | 1950 | 50 |
| -30 C (-22 F): Days with min | 50 | 44 | 1972 | 17 |
| -40 C (-40 F): Days with min | 22 | 9 | 1950 | 1 |
| 20 C (68 F): Tropical nights (min | 19 | 4 | 1941 | 1 |
| 10 mm (0.39 in): Days with 10 mm or more rain | 47 | 22 | 1953 | 12 |
| 25 mm (0.98 in): Days with 25 mm or more rain | 35 | 6 | 1954 | 4 |
| 50 mm (1.97 in): Days with 50 mm or more rain | 6 | 1 | 1935 | 1 |
| 100 mm (3.94 in): Days with 100 mm or more rain | 1 | 1 | 1983 | 1 |
| 10 cm (3.9 in): Days with 10 cm or more snowfall | 39 | 12 | 1948 | 1 |
| 25 cm (9.8 in): Days with 25 cm or more snowfall | 8 | 1 | 1939 | 1 |
| 50 cm (19.7 in): Days with 50 cm or more snowfall | 1 | 1 | 1941 | 1 |
Years with under 90 percent of days observed are left out of the most days column. Threshold history at this station starts in 1924.
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). Threshold counts are computed by this site.
Data as of . Last revised (2026-10-17).