Ottawa Weather Records (CA006105887)
Record envelope, standing records and threshold days for Ottawa (CA006105887), Ontario, Canada, with 64 years of record.
Key Facts for Ottawa
- Ottawa (CA006105887) is a weather station in Ontario, Canada at 45.40 latitude and -75.72 longitude, 72 m (236 ft) above sea level.
- The station reports from 1872 to 1935, 64 years of record.
- 1,464 records set at Ottawa still stand.
- Records are tracked for tmax, tmin, prcp, snow: an element needs 30 years of data to be eligible.
- Ottawa set a daily record high maximum temperature of 11.7 C (53.1 F) on 16 March 1935.
About the Station
- Location: Ontario, Canada, 45.40 latitude, -75.72 longitude.
- Elevation: 72 m (236 ft).
- Period of record: 1872 to 1935, 64 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 | 15.6 C (60.1 F) | -36.1 C (-33.0 F) | n/a | n/a |
| Feb | 12.2 C (54.0 F) | -36.1 C (-33.0 F) | n/a | n/a |
| Mar | 21.7 C (71.1 F) | -35.6 C (-32.1 F) | n/a | n/a |
| Apr | 30.0 C (86.0 F) | -19.4 C (-2.9 F) | n/a | n/a |
| May | 33.9 C (93.0 F) | -6.1 C (21.0 F) | n/a | n/a |
| Jun | 36.1 C (97.0 F) | 1.7 C (35.1 F) | n/a | n/a |
| Jul | 38.3 C (100.9 F) | 5.0 C (41.0 F) | n/a | n/a |
| Aug | 37.2 C (99.0 F) | 1.1 C (34.0 F) | n/a | n/a |
| Sep | 38.9 C (102.0 F) | -1.7 C (28.9 F) | n/a | n/a |
| Oct | 30.6 C (87.1 F) | -9.4 C (15.1 F) | n/a | n/a |
| Nov | 20.6 C (69.1 F) | -30.6 C (-23.1 F) | n/a | n/a |
| Dec | 12.8 C (55.0 F) | -36.7 C (-34.1 F) | n/a | n/a |
Which Years Hold Standing Records
1,464 standing records| Year set | Standing records |
|---|---|
| 1872 | 21 |
| 1873 | 28 |
| 1874 | 26 |
| 1875 | 46 |
| 1876 | 48 |
| 1877 | 6 |
| 1878 | 3 |
| 1879 | 51 |
| 1880 | 36 |
| 1881 | 9 |
| 1882 | 3 |
| 1883 | 31 |
| 1884 | 49 |
| 1885 | 59 |
| 1886 | 42 |
| 1887 | 41 |
| 1888 | 34 |
| 1889 | 30 |
| 1890 | 3 |
| 1899 | 11 |
| 1900 | 31 |
| 1901 | 21 |
| 1902 | 22 |
| 1903 | 31 |
| 1904 | 16 |
| 1905 | 11 |
| 1906 | 31 |
| 1907 | 21 |
| 1908 | 17 |
| 1909 | 16 |
| 1910 | 25 |
| 1911 | 31 |
| 1912 | 20 |
| 1913 | 33 |
| 1914 | 34 |
| 1915 | 30 |
| 1916 | 26 |
| 1917 | 21 |
| 1918 | 38 |
| 1919 | 28 |
| 1920 | 25 |
| 1921 | 27 |
| 1922 | 25 |
| 1923 | 28 |
| 1924 | 18 |
| 1925 | 31 |
| 1926 | 15 |
| 1927 | 17 |
| 1928 | 16 |
| 1929 | 20 |
| 1930 | 40 |
| 1931 | 36 |
| 1932 | 24 |
| 1933 | 32 |
| 1934 | 28 |
| 1935 | 2 |
All-Time Record Progression
4 new records| Date | Kind | Detail |
|---|---|---|
| 1931-07-02 | Record high maximum temperature | Record high maximum temperature 38.3 C (100.9 F) |
| 1931-09-11 | Record high maximum temperature | Record high maximum temperature 38.9 C (102.0 F) |
| 1933-12-29 | Record low maximum temperature | Record low maximum temperature -27.8 C (-18.0 F) |
| 1933-12-29 | Record low minimum temperature | Record low minimum temperature -36.7 C (-34.1 F) |
Wettest Day of Each Month
Oct: 94.0 mm (3.7 in)| Month | Record daily precipitation (mm) | Date |
|---|---|---|
| Jan | 48.8 mm (1.9 in) | 7 January 1905 |
| Feb | 50.8 mm (2.0 in) | 15 February 1876 |
| Mar | 71.1 mm (2.8 in) | 18 March 1881 |
| Apr | 50.8 mm (2.0 in) | 6 April 1885 |
| May | 53.3 mm (2.1 in) | 17 May 1916 |
| Jun | 53.8 mm (2.1 in) | 28 June 1928 |
| Jul | 57.4 mm (2.3 in) | 17 July 1900 |
| Aug | 71.1 mm (2.8 in) | 11 August 1887 |
| Sep | 61.7 mm (2.4 in) | 5 September 1918 |
| Oct | 94.0 mm (3.7 in) | 4 October 1887 |
| Nov | 54.1 mm (2.1 in) | 25 November 1912 |
| Dec | 38.6 mm (1.5 in) | 10 December 1878 |
Period of Record Coverage
1872 to 1935| Year | Days with data | Share of year | Complete |
|---|---|---|---|
| 1872 | 281 | 77% | No |
| 1873 | 352 | 96% | Yes |
| 1874 | 365 | 100% | Yes |
| 1875 | 365 | 100% | Yes |
| 1876 | 366 | 100% | Yes |
| 1877 | 96 | 26% | No |
| 1878 | 87 | 24% | No |
| 1879 | 350 | 96% | Yes |
| 1880 | 360 | 98% | Yes |
| 1881 | 155 | 42% | No |
| 1882 | 92 | 25% | No |
| 1883 | 365 | 100% | Yes |
| 1884 | 365 | 100% | Yes |
| 1885 | 365 | 100% | Yes |
| 1886 | 365 | 100% | Yes |
| 1887 | 364 | 100% | Yes |
| 1888 | 365 | 100% | Yes |
| 1889 | 365 | 100% | Yes |
| 1890 | 81 | 22% | No |
| 1899 | 245 | 67% | No |
| 1900 | 365 | 100% | Yes |
| 1901 | 365 | 100% | Yes |
| 1902 | 365 | 100% | Yes |
| 1903 | 365 | 100% | Yes |
| 1904 | 366 | 100% | Yes |
| 1905 | 365 | 100% | Yes |
| 1906 | 365 | 100% | Yes |
| 1907 | 365 | 100% | Yes |
| 1908 | 366 | 100% | Yes |
| 1909 | 365 | 100% | Yes |
| 1910 | 365 | 100% | Yes |
| 1911 | 365 | 100% | Yes |
| 1912 | 366 | 100% | Yes |
| 1913 | 365 | 100% | Yes |
| 1914 | 365 | 100% | Yes |
| 1915 | 365 | 100% | Yes |
| 1916 | 366 | 100% | Yes |
| 1917 | 365 | 100% | Yes |
| 1918 | 365 | 100% | Yes |
| 1919 | 365 | 100% | Yes |
| 1920 | 366 | 100% | Yes |
| 1921 | 365 | 100% | Yes |
| 1922 | 365 | 100% | Yes |
| 1923 | 365 | 100% | Yes |
| 1924 | 366 | 100% | Yes |
| 1925 | 365 | 100% | Yes |
| 1926 | 365 | 100% | Yes |
| 1927 | 365 | 100% | Yes |
| 1928 | 366 | 100% | Yes |
| 1929 | 365 | 100% | Yes |
| 1930 | 365 | 100% | Yes |
| 1931 | 365 | 100% | Yes |
| 1932 | 366 | 100% | Yes |
| 1933 | 365 | 100% | Yes |
| 1934 | 365 | 100% | Yes |
| 1935 | 89 | 24% | No |
Latest Records
20| Date | Station | Record | Value | Beat old record by | Old record stood | Significance |
|---|---|---|---|---|---|---|
| 16 March 1935 | Ottawa, CA | daily high max | 11.7 C (53.1 F) | 2.8 C (5.0 F) | 12 years | 13 of 100 (Routine) |
| 11 March 1935 | Ottawa, CA | daily high min (Tie) | 1.1 C (34.0 F) | tie | 32 years | 3 of 100 (Routine) |
| 15 February 1935 | Ottawa, CA | daily high min | -1.7 C (28.9 F) | 1.1 C (2.0 F) | 20 years | 13 of 100 (Routine) |
| 13 January 1935 | Ottawa, CA | daily snowfall | 14.0 cm (5.5 in) | 1.3 cm (0.5 in) | 59 years | 25 of 100 (Routine) |
| 8 January 1935 | Ottawa, CA | daily high max (Tie) | 3.9 C (39.0 F) | tie | 34 years | 4 of 100 (Routine) |
| 8 January 1935 | Ottawa, CA | daily high min (Tie) | 1.7 C (35.1 F) | tie | 7 years | 2 of 100 (Routine) |
| 26 December 1934 | Ottawa, CA | daily snowfall | 16.5 cm (6.5 in) | 9.4 cm (3.7 in) | 32 years | 32 of 100 (Routine) |
| 26 December 1934 | Ottawa, CA | daily rain | 16.5 mm (0.6 in) | 9.4 mm (0.37 in) | 32 years | 20 of 100 (Routine) |
| 19 December 1934 | Ottawa, CA | daily rain | 18.3 mm (0.7 in) | 0.3 mm (0.01 in) | 4 years | 7 of 100 (Routine) |
| 19 December 1934 | Ottawa, CA | daily snowfall | 18.3 cm (7.2 in) | 0.3 cm (0.1 in) | 4 years | 7 of 100 (Routine) |
| 1 December 1934 | Ottawa, CA | daily rain | 15.2 mm (0.6 in) | 5.0 mm (0.20 in) | 32 years | 20 of 100 (Routine) |
| 1 December 1934 | Ottawa, CA | daily high min | 3.9 C (39.0 F) | 1.1 C (2.0 F) | 11 years | 10 of 100 (Routine) |
| 30 November 1934 | Ottawa, CA | daily high min | 4.4 C (39.9 F) | 2.7 C (4.9 F) | 12 years | 14 of 100 (Routine) |
| 29 November 1934 | Ottawa, CA | daily high max | 12.8 C (55.0 F) | 0.6 C (1.1 F) | 54 years | 23 of 100 (Routine) |
| 29 November 1934 | Ottawa, CA | daily high min | 7.2 C (45.0 F) | 5.5 C (9.9 F) | 16 years | 20 of 100 (Routine) |
| 28 November 1934 | Ottawa, CA | daily high max | 12.8 C (55.0 F) | 1.1 C (2.0 F) | 54 years | 23 of 100 (Routine) |
| 23 November 1934 | Ottawa, CA | daily high max (Tie) | 13.9 C (57.0 F) | tie | 20 years | 3 of 100 (Routine) |
| 22 November 1934 | Ottawa, CA | daily high min | 8.3 C (46.9 F) | 2.7 C (4.9 F) | 27 years | 19 of 100 (Routine) |
| 17 November 1934 | Ottawa, CA | daily high max | 16.7 C (62.1 F) | 1.1 C (2.0 F) | 3 years | 7 of 100 (Routine) |
| 9 November 1934 | Ottawa, CA | daily snowfall | 6.4 cm (2.5 in) | 2.6 cm (1.0 in) | 12 years | 14 of 100 (Routine) |
Climate Trend
47 complete years, 1873 to 1934| Year | Annual mean temperature | Difference from the station mean |
|---|---|---|
| 1873 | 5.2 C | -0.37 C |
| 1874 | 5.3 C | -0.23 C |
| 1875 | 3.4 C | -2.11 C |
| 1876 | 5.3 C | -0.18 C |
| 1880 | 6.5 C | +0.98 C |
| 1883 | 3.5 C | -2.00 C |
| 1884 | 4.4 C | -1.13 C |
| 1885 | 3.1 C | -2.45 C |
| 1886 | 4.1 C | -1.43 C |
| 1887 | 4.4 C | -1.16 C |
| 1888 | 4.3 C | -1.21 C |
| 1889 | 5.8 C | +0.29 C |
| 1900 | 6.2 C | +0.64 C |
| 1901 | 6.0 C | +0.51 C |
| 1902 | 5.9 C | +0.41 C |
| 1903 | 6.0 C | +0.46 C |
| 1904 | 4.0 C | -1.55 C |
| 1905 | 5.3 C | -0.19 C |
| 1906 | 6.3 C | +0.77 C |
| 1907 | 4.9 C | -0.66 C |
| 1908 | 5.7 C | +0.21 C |
| 1909 | 5.2 C | -0.30 C |
| 1910 | 5.8 C | +0.32 C |
| 1911 | 5.7 C | +0.20 C |
| 1912 | 4.5 C | -1.00 C |
| 1913 | 6.4 C | +0.89 C |
| 1914 | 4.7 C | -0.81 C |
| 1915 | 6.5 C | +1.00 C |
| 1916 | 5.6 C | +0.07 C |
| 1917 | 3.9 C | -1.61 C |
| 1918 | 5.5 C | +0.01 C |
| 1919 | 6.5 C | +0.95 C |
| 1920 | 5.9 C | +0.42 C |
| 1921 | 7.4 C | +1.83 C |
| 1922 | 6.6 C | +1.04 C |
| 1923 | 5.4 C | -0.09 C |
| 1924 | 5.6 C | +0.11 C |
| 1925 | 5.7 C | +0.21 C |
| 1926 | 4.6 C | -0.88 C |
| 1927 | 6.4 C | +0.92 C |
| 1928 | 6.0 C | +0.45 C |
| 1929 | 6.0 C | +0.45 C |
| 1930 | 6.9 C | +1.35 C |
| 1931 | 8.1 C | +2.61 C |
| 1932 | 6.9 C | +1.39 C |
| 1933 | 6.4 C | +0.90 C |
| 1934 | 5.4 C | -0.11 C |
The annual mean temperature here has risen by 0.3 C (0.2 to 0.5) per decade over 1873 to 1934. In Fahrenheit: 0.6 F (0.3 to 0.8) per decade. The slope is a straight line fitted to 47 complete years; the brackets give its 95 percent interval.
| Measure | Per decade (C) | Per decade (F) | Period | Complete years | Reading |
|---|---|---|---|---|---|
| Annual mean temperature | 0.3 C (0.2 to 0.5) per decade | 0.6 F (0.3 to 0.8) per decade | 1873 to 1934 | 47 | Rise |
| Mean daily maximum | 0.3 C (0.1 to 0.4) per decade | 0.5 F (0.2 to 0.8) per decade | 1873 to 1934 | 47 | Rise |
| Mean daily minimum | 0.4 C (0.2 to 0.5) per decade | 0.7 F (0.4 to 0.9) per decade | 1873 to 1934 | 47 | 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
1872 to 1935| Measure | Record | Year of the record | Median year | Years with a value |
|---|---|---|---|---|
| Hottest day (TXx) | 38.9 C (102.0 F) | 1931 | 33.9 C (93.0 F) | 56 |
| Coldest night (TNn) | -36.7 C (-34.1 F) | 1933 | -30.8 C (-23.5 F) | 56 |
| Wettest day (Rx1day) | 94.0 mm (3.7 in) | 1887 | 39.9 mm (1.6 in) | 55 |
| Wettest five days (Rx5day) | 158.8 mm (6.3 in) | 1885 | 63.8 mm (2.5 in) | 55 |
| Longest dry spell (CDD) | 36 days | 1881 | 15 days | 55 |
Hottest day (TXx)
| Year | Hottest day (TXx) |
|---|---|
| 1872 | 34.4 C (93.9 F) |
| 1873 | 35.0 C (95.0 F) |
| 1874 | 34.4 C (93.9 F) |
| 1875 | 32.2 C (90.0 F) |
| 1876 | 37.2 C (99.0 F) |
| 1877 | 10.6 C (51.1 F) |
| 1878 | 24.4 C (75.9 F) |
| 1879 | 35.6 C (96.1 F) |
| 1880 | 33.9 C (93.0 F) |
| 1881 | 31.7 C (89.1 F) |
| 1882 | 26.1 C (79.0 F) |
| 1883 | 29.4 C (84.9 F) |
| 1884 | 34.4 C (93.9 F) |
| 1885 | 31.1 C (88.0 F) |
| 1886 | 31.7 C (89.1 F) |
| 1887 | 34.4 C (93.9 F) |
| 1888 | 35.0 C (95.0 F) |
| 1889 | 33.3 C (91.9 F) |
| 1890 | 10.0 C (50.0 F) |
| 1899 | 33.3 C (91.9 F) |
| 1900 | 31.7 C (89.1 F) |
| 1901 | 36.7 C (98.1 F) |
| 1902 | 32.2 C (90.0 F) |
| 1903 | 32.2 C (90.0 F) |
| 1904 | 34.4 C (93.9 F) |
| 1905 | 32.2 C (90.0 F) |
| 1906 | 35.0 C (95.0 F) |
| 1907 | 34.4 C (93.9 F) |
| 1908 | 34.4 C (93.9 F) |
| 1909 | 30.6 C (87.1 F) |
| 1910 | 31.1 C (88.0 F) |
| 1911 | 35.0 C (95.0 F) |
| 1912 | 32.8 C (91.0 F) |
| 1913 | 33.9 C (93.0 F) |
| 1914 | 31.1 C (88.0 F) |
| 1915 | 31.1 C (88.0 F) |
| 1916 | 36.1 C (97.0 F) |
| 1917 | 36.7 C (98.1 F) |
| 1918 | 34.4 C (93.9 F) |
| 1919 | 36.1 C (97.0 F) |
| 1920 | 33.9 C (93.0 F) |
| 1921 | 36.7 C (98.1 F) |
| 1922 | 33.9 C (93.0 F) |
| 1923 | 35.0 C (95.0 F) |
| 1924 | 32.8 C (91.0 F) |
| 1925 | 36.1 C (97.0 F) |
| 1926 | 31.1 C (88.0 F) |
| 1927 | 30.6 C (87.1 F) |
| 1928 | 33.3 C (91.9 F) |
| 1929 | 36.1 C (97.0 F) |
| 1930 | 33.3 C (91.9 F) |
| 1931 | 38.9 C (102.0 F) |
| 1932 | 33.3 C (91.9 F) |
| 1933 | 36.1 C (97.0 F) |
| 1934 | 34.4 C (93.9 F) |
| 1935 | 11.7 C (53.1 F) |
Coldest night (TNn)
| Year | Coldest night (TNn) |
|---|---|
| 1872 | -33.9 C (-29.0 F) |
| 1873 | -31.7 C (-25.1 F) |
| 1874 | -30.6 C (-23.1 F) |
| 1875 | -35.0 C (-31.0 F) |
| 1876 | -34.4 C (-29.9 F) |
| 1877 | -31.7 C (-25.1 F) |
| 1878 | -22.2 C (-8.0 F) |
| 1879 | -31.7 C (-25.1 F) |
| 1880 | -29.4 C (-20.9 F) |
| 1881 | -28.3 C (-18.9 F) |
| 1882 | -23.3 C (-9.9 F) |
| 1883 | -33.9 C (-29.0 F) |
| 1884 | -36.1 C (-33.0 F) |
| 1885 | -32.8 C (-27.0 F) |
| 1886 | -32.8 C (-27.0 F) |
| 1887 | -35.6 C (-32.1 F) |
| 1888 | -36.1 C (-33.0 F) |
| 1889 | -35.6 C (-32.1 F) |
| 1890 | -28.9 C (-20.0 F) |
| 1899 | -26.1 C (-15.0 F) |
| 1900 | -31.1 C (-24.0 F) |
| 1901 | -31.1 C (-24.0 F) |
| 1902 | -28.9 C (-20.0 F) |
| 1903 | -30.0 C (-22.0 F) |
| 1904 | -34.4 C (-29.9 F) |
| 1905 | -26.1 C (-15.0 F) |
| 1906 | -28.9 C (-20.0 F) |
| 1907 | -28.9 C (-20.0 F) |
| 1908 | -30.6 C (-23.1 F) |
| 1909 | -26.7 C (-16.1 F) |
| 1910 | -31.7 C (-25.1 F) |
| 1911 | -28.9 C (-20.0 F) |
| 1912 | -32.8 C (-27.0 F) |
| 1913 | -27.8 C (-18.0 F) |
| 1914 | -34.4 C (-29.9 F) |
| 1915 | -31.1 C (-24.0 F) |
| 1916 | -28.9 C (-20.0 F) |
| 1917 | -35.0 C (-31.0 F) |
| 1918 | -32.8 C (-27.0 F) |
| 1919 | -28.9 C (-20.0 F) |
| 1920 | -33.9 C (-29.0 F) |
| 1921 | -30.6 C (-23.1 F) |
| 1922 | -29.4 C (-20.9 F) |
| 1923 | -35.0 C (-31.0 F) |
| 1924 | -33.3 C (-27.9 F) |
| 1925 | -33.9 C (-29.0 F) |
| 1926 | -30.6 C (-23.1 F) |
| 1927 | -30.0 C (-22.0 F) |
| 1928 | -28.3 C (-18.9 F) |
| 1929 | -29.4 C (-20.9 F) |
| 1930 | -28.9 C (-20.0 F) |
| 1931 | -29.4 C (-20.9 F) |
| 1932 | -28.3 C (-18.9 F) |
| 1933 | -36.7 C (-34.1 F) |
| 1934 | -33.3 C (-27.9 F) |
| 1935 | -30.6 C (-23.1 F) |
Wettest day (Rx1day)
| Year | Wettest day (Rx1day) |
|---|---|
| 1872 | 33.0 mm (1.3 in) |
| 1873 | 36.8 mm (1.4 in) |
| 1874 | 25.4 mm (1.0 in) |
| 1875 | 38.1 mm (1.5 in) |
| 1876 | 50.8 mm (2.0 in) |
| 1877 | 30.5 mm (1.2 in) |
| 1878 | 38.6 mm (1.5 in) |
| 1879 | 38.1 mm (1.5 in) |
| 1880 | 40.9 mm (1.6 in) |
| 1881 | 71.1 mm (2.8 in) |
| 1882 | 15.2 mm (0.6 in) |
| 1883 | 40.1 mm (1.6 in) |
| 1884 | 36.1 mm (1.4 in) |
| 1885 | 50.8 mm (2.0 in) |
| 1886 | 54.1 mm (2.1 in) |
| 1887 | 94.0 mm (3.7 in) |
| 1888 | 36.3 mm (1.4 in) |
| 1889 | 25.1 mm (1.0 in) |
| 1890 | n/a |
| 1899 | 41.1 mm (1.6 in) |
| 1900 | 57.4 mm (2.3 in) |
| 1901 | 39.1 mm (1.5 in) |
| 1902 | 43.2 mm (1.7 in) |
| 1903 | 41.9 mm (1.6 in) |
| 1904 | 44.7 mm (1.8 in) |
| 1905 | 53.1 mm (2.1 in) |
| 1906 | 41.1 mm (1.6 in) |
| 1907 | 47.8 mm (1.9 in) |
| 1908 | 39.6 mm (1.6 in) |
| 1909 | 37.6 mm (1.5 in) |
| 1910 | 39.9 mm (1.6 in) |
| 1911 | 36.3 mm (1.4 in) |
| 1912 | 54.1 mm (2.1 in) |
| 1913 | 54.1 mm (2.1 in) |
| 1914 | 22.9 mm (0.9 in) |
| 1915 | 43.7 mm (1.7 in) |
| 1916 | 53.3 mm (2.1 in) |
| 1917 | 34.8 mm (1.4 in) |
| 1918 | 61.7 mm (2.4 in) |
| 1919 | 46.0 mm (1.8 in) |
| 1920 | 38.9 mm (1.5 in) |
| 1921 | 51.6 mm (2.0 in) |
| 1922 | 30.5 mm (1.2 in) |
| 1923 | 42.9 mm (1.7 in) |
| 1924 | 26.7 mm (1.1 in) |
| 1925 | 38.9 mm (1.5 in) |
| 1926 | 50.0 mm (2.0 in) |
| 1927 | 43.4 mm (1.7 in) |
| 1928 | 53.8 mm (2.1 in) |
| 1929 | 31.0 mm (1.2 in) |
| 1930 | 34.0 mm (1.3 in) |
| 1931 | 27.2 mm (1.1 in) |
| 1932 | 39.4 mm (1.6 in) |
| 1933 | 41.4 mm (1.6 in) |
| 1934 | 39.9 mm (1.6 in) |
| 1935 | 14.2 mm (0.6 in) |
Wettest five days (Rx5day)
| Year | Wettest five days (Rx5day) |
|---|---|
| 1872 | 43.0 mm (1.7 in) |
| 1873 | 59.2 mm (2.3 in) |
| 1874 | 59.7 mm (2.4 in) |
| 1875 | 61.0 mm (2.4 in) |
| 1876 | 72.9 mm (2.9 in) |
| 1877 | 58.4 mm (2.3 in) |
| 1878 | 63.3 mm (2.5 in) |
| 1879 | 44.2 mm (1.7 in) |
| 1880 | 44.7 mm (1.8 in) |
| 1881 | 82.3 mm (3.2 in) |
| 1882 | 33.0 mm (1.3 in) |
| 1883 | 45.4 mm (1.8 in) |
| 1884 | 57.1 mm (2.2 in) |
| 1885 | 158.8 mm (6.3 in) |
| 1886 | 119.4 mm (4.7 in) |
| 1887 | 107.7 mm (4.2 in) |
| 1888 | 76.9 mm (3.0 in) |
| 1889 | 65.8 mm (2.6 in) |
| 1890 | n/a |
| 1899 | 87.9 mm (3.5 in) |
| 1900 | 78.8 mm (3.1 in) |
| 1901 | 56.1 mm (2.2 in) |
| 1902 | 57.2 mm (2.3 in) |
| 1903 | 75.7 mm (3.0 in) |
| 1904 | 55.0 mm (2.2 in) |
| 1905 | 69.4 mm (2.7 in) |
| 1906 | 75.9 mm (3.0 in) |
| 1907 | 76.5 mm (3.0 in) |
| 1908 | 55.9 mm (2.2 in) |
| 1909 | 58.2 mm (2.3 in) |
| 1910 | 61.5 mm (2.4 in) |
| 1911 | 38.3 mm (1.5 in) |
| 1912 | 67.7 mm (2.7 in) |
| 1913 | 71.6 mm (2.8 in) |
| 1914 | 58.9 mm (2.3 in) |
| 1915 | 77.3 mm (3.0 in) |
| 1916 | 94.2 mm (3.7 in) |
| 1917 | 57.9 mm (2.3 in) |
| 1918 | 75.7 mm (3.0 in) |
| 1919 | 63.8 mm (2.5 in) |
| 1920 | 59.0 mm (2.3 in) |
| 1921 | 85.6 mm (3.4 in) |
| 1922 | 44.5 mm (1.8 in) |
| 1923 | 73.9 mm (2.9 in) |
| 1924 | 59.0 mm (2.3 in) |
| 1925 | 77.5 mm (3.1 in) |
| 1926 | 80.0 mm (3.1 in) |
| 1927 | 74.5 mm (2.9 in) |
| 1928 | 84.0 mm (3.3 in) |
| 1929 | 49.8 mm (2.0 in) |
| 1930 | 66.2 mm (2.6 in) |
| 1931 | 36.3 mm (1.4 in) |
| 1932 | 78.5 mm (3.1 in) |
| 1933 | 58.7 mm (2.3 in) |
| 1934 | 73.7 mm (2.9 in) |
| 1935 | 29.2 mm (1.1 in) |
Longest dry spell (CDD)
| Year | Longest dry spell (CDD) |
|---|---|
| 1872 | 14 days |
| 1873 | 23 days |
| 1874 | 12 days |
| 1875 | 19 days |
| 1876 | 17 days |
| 1877 | 13 days |
| 1878 | 7 days |
| 1879 | 27 days |
| 1880 | 12 days |
| 1881 | 36 days |
| 1882 | 7 days |
| 1883 | 15 days |
| 1884 | 15 days |
| 1885 | 17 days |
| 1886 | 12 days |
| 1887 | 18 days |
| 1888 | 22 days |
| 1889 | 24 days |
| 1890 | n/a |
| 1899 | 17 days |
| 1900 | 18 days |
| 1901 | 15 days |
| 1902 | 15 days |
| 1903 | 23 days |
| 1904 | 16 days |
| 1905 | 14 days |
| 1906 | 17 days |
| 1907 | 11 days |
| 1908 | 13 days |
| 1909 | 14 days |
| 1910 | 12 days |
| 1911 | 17 days |
| 1912 | 18 days |
| 1913 | 18 days |
| 1914 | 16 days |
| 1915 | 22 days |
| 1916 | 13 days |
| 1917 | 18 days |
| 1918 | 12 days |
| 1919 | 15 days |
| 1920 | 11 days |
| 1921 | 14 days |
| 1922 | 18 days |
| 1923 | 14 days |
| 1924 | 20 days |
| 1925 | 14 days |
| 1926 | 10 days |
| 1927 | 15 days |
| 1928 | 15 days |
| 1929 | 13 days |
| 1930 | 17 days |
| 1931 | 14 days |
| 1932 | 19 days |
| 1933 | 12 days |
| 1934 | 19 days |
| 1935 | 11 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
47 years with a frostAcross 47 years with a frost, the median last spring frost at Ottawa falls on 4 May and the median first autumn frost on 7 October, which leaves a median of 153 days between them.
Fitted over all years, the growing season changes by +2.0 days per decade at this station.
| Measure | Median, all years | Earliest period | Recent period (1905 to 1934) | Recent against earliest | Fitted trend |
|---|---|---|---|---|---|
| Last spring frost | 4 May | n/a | 4 May | n/a | -0.1 days per decade |
| First autumn frost | 7 October | n/a | 8 October | n/a | +2.0 days per decade |
| Growing days | 153 days | n/a | 155 days | n/a | +2.0 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
45 years, 1873 to 1934A day with at least 41.6 mm (1.6 in) of rain is expected about once in 2 years. A day with at least 76.6 mm (3.0 in) of rain is expected about once in 100 years.
| Expected about once in | A day with at least | Note |
|---|---|---|
| 2 years | 41.6 mm (1.6 in) | |
| 5 years | 51.5 mm (2.0 in) | |
| 10 years | 57.9 mm (2.3 in) | |
| 25 years | 65.6 mm (2.6 in) | |
| 50 years | 71.2 mm (2.8 in) | Longer than the 45 years of record |
| 100 years | 76.6 mm (3.0 in) | Longer than the 45 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, 45 years of values from 1873 to 1934.
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: 94.0 mm (3.7 in) in 1887; 61.7 mm (2.4 in) in 1918; 57.4 mm (2.3 in) in 1900.
Station Changes
1 suspectedOne change was suspected in the annual mean temperature of Ottawa, at 1900. Each is measured against neighbouring stations.
- Relative to 5 neighbouring stations, the station's annual mean temperature from 1900 ran 0.8 C (1.4 F) higher than in the years before (likely change).
| Year | Shift (C) | Shift (F) | Strength | Neighbours |
|---|---|---|---|---|
| 1900 | +0.8 | +1.4 | likely | 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).