Record highRecord low2026 daily maximum2026 daily minimum
The band shows the record high and record low for each calendar day at Ottawa Cda. The lines show the 2026 daily maximum and minimum. 0 days in 2026 matched or passed a record. Temperatures are in degrees Celsius.
Daily record high and record low at Ottawa Cda, with 2026 drawn through them
Month
Highest record high
Lowest record low
2026 highest maximum
2026 lowest minimum
Jan
11.7 C (53.1 F)
-37.8 C (-36.0 F)
n/a
n/a
Feb
12.2 C (54.0 F)
-38.3 C (-36.9 F)
n/a
n/a
Mar
25.6 C (78.1 F)
-36.7 C (-34.1 F)
n/a
n/a
Apr
30.6 C (87.1 F)
-20.6 C (-5.1 F)
n/a
n/a
May
35.0 C (95.0 F)
-7.2 C (19.0 F)
n/a
n/a
Jun
36.7 C (98.1 F)
0.0 C (32.0 F)
n/a
n/a
Jul
37.8 C (100.0 F)
3.3 C (37.9 F)
n/a
n/a
Aug
37.8 C (100.0 F)
1.7 C (35.1 F)
n/a
n/a
Sep
36.7 C (98.1 F)
-4.4 C (24.1 F)
n/a
n/a
Oct
29.4 C (84.9 F)
-12.8 C (9.0 F)
n/a
n/a
Nov
23.3 C (73.9 F)
-23.9 C (-11.0 F)
n/a
n/a
Dec
16.1 C (61.0 F)
-38.9 C (-38.0 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at Ottawa Cda still stand. 1933 holds the most, with 46.
Standing records at Ottawa Cda by the year they were set
Year set
Standing records
1889
3
1890
12
1891
23
1892
13
1893
17
1894
18
1895
25
1896
20
1897
19
1898
13
1899
7
1900
10
1901
11
1902
9
1903
9
1904
8
1905
6
1906
16
1907
15
1908
16
1909
9
1910
8
1911
22
1912
8
1913
24
1914
23
1915
13
1916
27
1917
13
1918
12
1919
20
1920
13
1921
19
1922
14
1923
15
1924
10
1925
17
1926
16
1927
5
1928
13
1929
17
1930
19
1931
28
1932
20
1933
46
1934
41
1935
6
1936
16
1937
7
1938
10
1939
11
1940
26
1941
17
1942
18
1943
20
1944
19
1945
24
1946
24
1947
31
1948
14
1949
19
1950
19
1951
20
1952
7
1953
23
1954
12
1955
15
1956
18
1957
21
1958
9
1959
14
1960
5
1961
9
1962
11
1963
17
1964
13
1965
14
1966
13
1967
9
1968
13
1969
12
1970
7
1971
9
1972
8
1973
10
1974
11
1975
13
1976
17
1977
19
1978
8
1979
21
1980
13
1981
26
1982
15
1983
9
All-Time Record Progression
7 new records
7 all-time records were set at Ottawa Cda between 4 February 1923 and 21 July 1977. Each dot is a new record.
When Ottawa Cda set new all-time records
Date
Kind
Detail
1923-02-04
Record low minimum temperature
Record low minimum temperature -36.1 C (-33.0 F)
1925-01-19
Record low minimum temperature
Record low minimum temperature -37.8 C (-36.0 F)
1933-12-29
Record low maximum temperature
Record low maximum temperature -31.7 C (-25.1 F)
1933-12-29
Record low minimum temperature
Record low minimum temperature -38.9 C (-38.0 F)
1942-09-09
Record daily precipitation
Record daily precipitation 93.2 mm (3.7 in)
1969-07-17
Record high minimum temperature
Record high minimum temperature 23.9 C (75.0 F)
1977-07-21
Record high minimum temperature
Record high minimum temperature 24.0 C (75.2 F)
Wettest Day of Each Month
Sep: 93.2 mm (3.7 in)
The wettest day on record for each calendar month at Ottawa Cda. The most was 93.2 mm (3.7 in) on 9 September 1942.
Record daily precipitation for each month at Ottawa Cda
Month
Record daily precipitation (mm)
Date
Jan
55.9 mm (2.2 in)
29 January 1894
Feb
45.7 mm (1.8 in)
8 February 1895
Mar
48.8 mm (1.9 in)
12 March 1962
Apr
48.3 mm (1.9 in)
15 April 1956
May
75.9 mm (3.0 in)
17 May 1916
Jun
77.5 mm (3.1 in)
17 June 1946
Jul
74.2 mm (2.9 in)
11 July 1899
Aug
90.4 mm (3.6 in)
23 August 1943
Sep
93.2 mm (3.7 in)
9 September 1942
Oct
51.6 mm (2.0 in)
25 October 1980
Nov
53.3 mm (2.1 in)
25 November 1912
Dec
73.2 mm (2.9 in)
31 December 1933
Period of Record Coverage
1889 to 1983
Complete yearUnder 90 percent of days
95 years of record at Ottawa Cda, 1889 to 1983. 1 years have data for under 90 percent of days and are left out of rankings: 1889.
Cooler than the station meanWarmer than the station mean
One stripe for each of 93 complete years at Ottawa Cda, 1890 to 1983. Blue stripes are years cooler than the station's own mean of 5.6 C (42.0 F); red stripes are warmer. The coolest year was 1904, at 3.7 C (38.6 F), and the warmest was 1953, at 7.6 C (45.6 F). The strongest colour marks a difference of 2.0 C (3.6 F).
Annual mean temperature at Ottawa Cda as warming stripes, 1890 to 1983
Year
Annual mean temperature
Difference from the station mean
1890
4.7 C
-0.89 C
1891
6.1 C
+0.55 C
1892
5.1 C
-0.48 C
1893
4.3 C
-1.30 C
1894
6.0 C
+0.44 C
1895
5.3 C
-0.22 C
1896
5.3 C
-0.30 C
1897
5.7 C
+0.15 C
1898
6.6 C
+1.07 C
1900
6.1 C
+0.50 C
1901
5.8 C
+0.23 C
1902
5.7 C
+0.18 C
1903
5.6 C
-0.01 C
1904
3.7 C
-1.89 C
1905
4.7 C
-0.86 C
1906
5.7 C
+0.18 C
1907
4.3 C
-1.29 C
1908
5.5 C
-0.09 C
1909
5.5 C
-0.08 C
1910
6.1 C
+0.50 C
1911
6.1 C
+0.52 C
1912
4.7 C
-0.82 C
1913
6.7 C
+1.11 C
1914
5.1 C
-0.49 C
1915
6.6 C
+1.02 C
1916
5.3 C
-0.24 C
1917
3.7 C
-1.84 C
1918
5.2 C
-0.41 C
1919
6.0 C
+0.48 C
1920
5.6 C
+0.07 C
1921
7.2 C
+1.64 C
1922
6.1 C
+0.58 C
1923
5.1 C
-0.47 C
1924
4.9 C
-0.62 C
1925
5.2 C
-0.34 C
1926
3.9 C
-1.67 C
1927
5.7 C
+0.16 C
1928
5.0 C
-0.53 C
1929
4.6 C
-0.94 C
1930
5.7 C
+0.15 C
1931
6.7 C
+1.10 C
1932
5.5 C
-0.02 C
1933
5.1 C
-0.49 C
1934
3.9 C
-1.69 C
1935
4.4 C
-1.16 C
1936
4.6 C
-1.01 C
1937
6.1 C
+0.57 C
1938
5.6 C
+0.04 C
1939
4.4 C
-1.12 C
1940
4.2 C
-1.33 C
1941
5.5 C
-0.06 C
1942
5.8 C
+0.26 C
1943
4.3 C
-1.31 C
1944
5.6 C
+0.06 C
1945
5.3 C
-0.28 C
1946
5.7 C
+0.11 C
1947
5.3 C
-0.25 C
1948
6.1 C
+0.50 C
1949
6.6 C
+1.07 C
1950
5.4 C
-0.19 C
1951
5.9 C
+0.34 C
1952
6.6 C
+1.07 C
1953
7.6 C
+1.99 C
1954
5.5 C
-0.07 C
1955
6.2 C
+0.60 C
1956
5.1 C
-0.44 C
1957
6.4 C
+0.85 C
1958
5.3 C
-0.30 C
1959
5.9 C
+0.29 C
1960
6.2 C
+0.61 C
1961
6.1 C
+0.56 C
1962
5.3 C
-0.23 C
1963
5.2 C
-0.36 C
1964
6.3 C
+0.72 C
1965
5.6 C
+0.01 C
1966
6.2 C
+0.59 C
1967
5.6 C
-0.01 C
1968
5.9 C
+0.29 C
1969
6.1 C
+0.53 C
1970
5.5 C
-0.07 C
1971
5.5 C
-0.05 C
1972
4.8 C
-0.74 C
1973
6.9 C
+1.35 C
1974
5.6 C
-0.01 C
1975
6.6 C
+1.08 C
1976
5.1 C
-0.44 C
1977
6.3 C
+0.74 C
1978
5.4 C
-0.16 C
1979
6.4 C
+0.82 C
1980
5.4 C
-0.19 C
1981
6.6 C
+1.04 C
1982
5.8 C
+0.21 C
1983
6.6 C
+1.00 C
The annual mean temperature here has risen by 0.07 C (0.02 to 0.13) per decade over 1890 to 1983. In Fahrenheit: 0.13 F (0.03 to 0.24) per decade. The slope is a straight line fitted to 93 complete years; the brackets give its 95 percent interval.
Fitted temperature trends per decade at Ottawa Cda
Measure
Per decade (C)
Per decade (F)
Period
Complete years
Reading
Annual mean temperature
0.07 C (0.02 to 0.13) per decade
0.13 F (0.03 to 0.24) per decade
1890 to 1983
93
Rise
Mean daily maximum
-0.02 C (-0.08 to 0.03) per decade
-0.04 F (-0.15 to 0.06) per decade
1890 to 1983
93
Not clearly different from zero
Mean daily minimum
0.2 C (0.1 to 0.2) per decade
0.3 F (0.2 to 0.4) per decade
1890 to 1983
93
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
1889 to 1983
Yearly extremes at Ottawa Cda: the record and the median year
Measure
Record
Year of the record
Median year
Years with a value
Hottest day (TXx)
37.8 C (100.0 F)
1913
33.9 C (93.0 F)
95
Coldest night (TNn)
-38.9 C (-38.0 F)
1933
-32.0 C (-25.6 F)
95
Wettest day (Rx1day)
93.2 mm (3.7 in)
1942
43.4 mm (1.7 in)
95
Wettest five days (Rx5day)
129.2 mm (5.1 in)
1939
67.3 mm (2.6 in)
95
Longest dry spell (CDD)
36 days
1961
15 days
95
Hottest day (TXx)
The hottest day of the year at Ottawa Cda, 1889 to 1983. The record is 37.8 C (100.0 F) in 1913, marked on the chart; the median year is 33.9 C (93.0 F).
Hottest day (TXx) at Ottawa Cda by year
Year
Hottest day (TXx)
1889
14.4 C (57.9 F)
1890
33.9 C (93.0 F)
1891
33.9 C (93.0 F)
1892
36.1 C (97.0 F)
1893
35.0 C (95.0 F)
1894
33.9 C (93.0 F)
1895
34.4 C (93.9 F)
1896
33.9 C (93.0 F)
1897
36.1 C (97.0 F)
1898
35.0 C (95.0 F)
1899
34.4 C (93.9 F)
1900
34.4 C (93.9 F)
1901
37.2 C (99.0 F)
1902
33.3 C (91.9 F)
1903
32.8 C (91.0 F)
1904
35.0 C (95.0 F)
1905
32.8 C (91.0 F)
1906
36.1 C (97.0 F)
1907
35.6 C (96.1 F)
1908
35.6 C (96.1 F)
1909
35.6 C (96.1 F)
1910
33.9 C (93.0 F)
1911
36.7 C (98.1 F)
1912
35.6 C (96.1 F)
1913
37.8 C (100.0 F)
1914
33.9 C (93.0 F)
1915
33.3 C (91.9 F)
1916
37.8 C (100.0 F)
1917
37.8 C (100.0 F)
1918
35.6 C (96.1 F)
1919
37.2 C (99.0 F)
1920
34.4 C (93.9 F)
1921
37.8 C (100.0 F)
1922
34.4 C (93.9 F)
1923
35.0 C (95.0 F)
1924
35.0 C (95.0 F)
1925
33.9 C (93.0 F)
1926
30.6 C (87.1 F)
1927
30.6 C (87.1 F)
1928
31.1 C (88.0 F)
1929
34.4 C (93.9 F)
1930
31.7 C (89.1 F)
1931
37.2 C (99.0 F)
1932
31.7 C (89.1 F)
1933
33.9 C (93.0 F)
1934
34.4 C (93.9 F)
1935
33.3 C (91.9 F)
1936
35.6 C (96.1 F)
1937
33.9 C (93.0 F)
1938
33.9 C (93.0 F)
1939
33.9 C (93.0 F)
1940
32.2 C (90.0 F)
1941
35.6 C (96.1 F)
1942
33.3 C (91.9 F)
1943
32.2 C (90.0 F)
1944
37.8 C (100.0 F)
1945
32.2 C (90.0 F)
1946
33.9 C (93.0 F)
1947
35.0 C (95.0 F)
1948
35.0 C (95.0 F)
1949
36.1 C (97.0 F)
1950
31.1 C (88.0 F)
1951
31.1 C (88.0 F)
1952
32.8 C (91.0 F)
1953
35.6 C (96.1 F)
1954
31.1 C (88.0 F)
1955
37.2 C (99.0 F)
1956
34.4 C (93.9 F)
1957
32.8 C (91.0 F)
1958
30.6 C (87.1 F)
1959
35.0 C (95.0 F)
1960
32.2 C (90.0 F)
1961
31.1 C (88.0 F)
1962
33.9 C (93.0 F)
1963
35.6 C (96.1 F)
1964
34.4 C (93.9 F)
1965
32.8 C (91.0 F)
1966
35.0 C (95.0 F)
1967
31.7 C (89.1 F)
1968
33.3 C (91.9 F)
1969
33.3 C (91.9 F)
1970
33.3 C (91.9 F)
1971
32.8 C (91.0 F)
1972
31.7 C (89.1 F)
1973
34.4 C (93.9 F)
1974
32.2 C (90.0 F)
1975
35.6 C (96.1 F)
1976
31.7 C (89.1 F)
1977
34.5 C (94.1 F)
1978
34.0 C (93.2 F)
1979
32.5 C (90.5 F)
1980
32.0 C (89.6 F)
1981
33.0 C (91.4 F)
1982
35.0 C (95.0 F)
1983
33.5 C (92.3 F)
Coldest night (TNn)
The coldest night of the year at Ottawa Cda, 1889 to 1983. The record is -38.9 C (-38.0 F) in 1933, marked on the chart; the median year is -32.0 C (-25.6 F).
Coldest night (TNn) at Ottawa Cda by year
Year
Coldest night (TNn)
1889
-23.3 C (-9.9 F)
1890
-28.9 C (-20.0 F)
1891
-32.8 C (-27.0 F)
1892
-31.1 C (-24.0 F)
1893
-32.2 C (-26.0 F)
1894
-32.2 C (-26.0 F)
1895
-30.6 C (-23.1 F)
1896
-35.0 C (-31.0 F)
1897
-32.2 C (-26.0 F)
1898
-31.7 C (-25.1 F)
1899
-31.1 C (-24.0 F)
1900
-30.0 C (-22.0 F)
1901
-32.2 C (-26.0 F)
1902
-31.7 C (-25.1 F)
1903
-34.4 C (-29.9 F)
1904
-34.4 C (-29.9 F)
1905
-28.9 C (-20.0 F)
1906
-31.7 C (-25.1 F)
1907
-30.6 C (-23.1 F)
1908
-35.0 C (-31.0 F)
1909
-27.8 C (-18.0 F)
1910
-31.7 C (-25.1 F)
1911
-27.8 C (-18.0 F)
1912
-32.2 C (-26.0 F)
1913
-27.8 C (-18.0 F)
1914
-34.4 C (-29.9 F)
1915
-31.7 C (-25.1 F)
1916
-28.9 C (-20.0 F)
1917
-35.0 C (-31.0 F)
1918
-33.3 C (-27.9 F)
1919
-30.0 C (-22.0 F)
1920
-33.9 C (-29.0 F)
1921
-30.0 C (-22.0 F)
1922
-30.0 C (-22.0 F)
1923
-36.1 C (-33.0 F)
1924
-34.4 C (-29.9 F)
1925
-37.8 C (-36.0 F)
1926
-31.1 C (-24.0 F)
1927
-33.9 C (-29.0 F)
1928
-31.7 C (-25.1 F)
1929
-32.2 C (-26.0 F)
1930
-34.4 C (-29.9 F)
1931
-32.8 C (-27.0 F)
1932
-30.0 C (-22.0 F)
1933
-38.9 C (-38.0 F)
1934
-38.3 C (-36.9 F)
1935
-33.3 C (-27.9 F)
1936
-30.0 C (-22.0 F)
1937
-30.6 C (-23.1 F)
1938
-36.7 C (-34.1 F)
1939
-32.8 C (-27.0 F)
1940
-32.8 C (-27.0 F)
1941
-31.7 C (-25.1 F)
1942
-36.7 C (-34.1 F)
1943
-37.8 C (-36.0 F)
1944
-35.0 C (-31.0 F)
1945
-33.9 C (-29.0 F)
1946
-32.8 C (-27.0 F)
1947
-30.6 C (-23.1 F)
1948
-36.1 C (-33.0 F)
1949
-28.9 C (-20.0 F)
1950
-33.9 C (-29.0 F)
1951
-36.1 C (-33.0 F)
1952
-36.1 C (-33.0 F)
1953
-28.9 C (-20.0 F)
1954
-31.7 C (-25.1 F)
1955
-32.2 C (-26.0 F)
1956
-28.9 C (-20.0 F)
1957
-37.2 C (-35.0 F)
1958
-32.2 C (-26.0 F)
1959
-33.3 C (-27.9 F)
1960
-28.9 C (-20.0 F)
1961
-28.9 C (-20.0 F)
1962
-32.2 C (-26.0 F)
1963
-32.2 C (-26.0 F)
1964
-30.0 C (-22.0 F)
1965
-30.0 C (-22.0 F)
1966
-28.3 C (-18.9 F)
1967
-33.3 C (-27.9 F)
1968
-32.8 C (-27.0 F)
1969
-23.9 C (-11.0 F)
1970
-31.1 C (-24.0 F)
1971
-32.8 C (-27.0 F)
1972
-31.7 C (-25.1 F)
1973
-30.0 C (-22.0 F)
1974
-26.7 C (-16.1 F)
1975
-29.4 C (-20.9 F)
1976
-32.8 C (-27.0 F)
1977
-30.0 C (-22.0 F)
1978
-26.0 C (-14.8 F)
1979
-30.0 C (-22.0 F)
1980
-32.0 C (-25.6 F)
1981
-35.0 C (-31.0 F)
1982
-32.0 C (-25.6 F)
1983
-27.3 C (-17.1 F)
Wettest day (Rx1day)
The wettest day of the year at Ottawa Cda, 1889 to 1983. The record is 93.2 mm (3.7 in) in 1942, marked on the chart; the median year is 43.4 mm (1.7 in).
Wettest day (Rx1day) at Ottawa Cda by year
Year
Wettest day (Rx1day)
1889
20.3 mm (0.8 in)
1890
42.9 mm (1.7 in)
1891
53.8 mm (2.1 in)
1892
49.8 mm (2.0 in)
1893
50.0 mm (2.0 in)
1894
55.9 mm (2.2 in)
1895
57.7 mm (2.3 in)
1896
50.0 mm (2.0 in)
1897
28.4 mm (1.1 in)
1898
28.4 mm (1.1 in)
1899
74.2 mm (2.9 in)
1900
59.4 mm (2.3 in)
1901
39.4 mm (1.6 in)
1902
53.1 mm (2.1 in)
1903
51.6 mm (2.0 in)
1904
42.7 mm (1.7 in)
1905
49.3 mm (1.9 in)
1906
39.6 mm (1.6 in)
1907
49.0 mm (1.9 in)
1908
36.3 mm (1.4 in)
1909
36.1 mm (1.4 in)
1910
37.3 mm (1.5 in)
1911
37.6 mm (1.5 in)
1912
53.3 mm (2.1 in)
1913
43.2 mm (1.7 in)
1914
30.0 mm (1.2 in)
1915
46.2 mm (1.8 in)
1916
75.9 mm (3.0 in)
1917
29.5 mm (1.2 in)
1918
58.7 mm (2.3 in)
1919
46.0 mm (1.8 in)
1920
26.9 mm (1.1 in)
1921
47.5 mm (1.9 in)
1922
40.1 mm (1.6 in)
1923
43.9 mm (1.7 in)
1924
34.8 mm (1.4 in)
1925
28.7 mm (1.1 in)
1926
49.5 mm (1.9 in)
1927
41.9 mm (1.6 in)
1928
48.3 mm (1.9 in)
1929
38.1 mm (1.5 in)
1930
34.5 mm (1.4 in)
1931
28.4 mm (1.1 in)
1932
45.0 mm (1.8 in)
1933
73.2 mm (2.9 in)
1934
38.6 mm (1.5 in)
1935
46.5 mm (1.8 in)
1936
27.9 mm (1.1 in)
1937
37.8 mm (1.5 in)
1938
71.6 mm (2.8 in)
1939
52.3 mm (2.1 in)
1940
34.0 mm (1.3 in)
1941
40.6 mm (1.6 in)
1942
93.2 mm (3.7 in)
1943
90.4 mm (3.6 in)
1944
30.0 mm (1.2 in)
1945
60.5 mm (2.4 in)
1946
77.5 mm (3.1 in)
1947
50.3 mm (2.0 in)
1948
36.3 mm (1.4 in)
1949
30.2 mm (1.2 in)
1950
68.1 mm (2.7 in)
1951
39.9 mm (1.6 in)
1952
61.0 mm (2.4 in)
1953
38.9 mm (1.5 in)
1954
41.1 mm (1.6 in)
1955
48.3 mm (1.9 in)
1956
48.3 mm (1.9 in)
1957
42.7 mm (1.7 in)
1958
43.4 mm (1.7 in)
1959
44.5 mm (1.8 in)
1960
45.2 mm (1.8 in)
1961
29.5 mm (1.2 in)
1962
48.8 mm (1.9 in)
1963
54.9 mm (2.2 in)
1964
30.5 mm (1.2 in)
1965
36.1 mm (1.4 in)
1966
30.5 mm (1.2 in)
1967
48.3 mm (1.9 in)
1968
35.8 mm (1.4 in)
1969
51.1 mm (2.0 in)
1970
41.1 mm (1.6 in)
1971
71.1 mm (2.8 in)
1972
50.5 mm (2.0 in)
1973
60.5 mm (2.4 in)
1974
40.6 mm (1.6 in)
1975
30.2 mm (1.2 in)
1976
35.6 mm (1.4 in)
1977
43.6 mm (1.7 in)
1978
34.0 mm (1.3 in)
1979
39.4 mm (1.6 in)
1980
51.6 mm (2.0 in)
1981
51.2 mm (2.0 in)
1982
28.6 mm (1.1 in)
1983
33.8 mm (1.3 in)
Wettest five days (Rx5day)
The wettest five days of the year at Ottawa Cda, 1889 to 1983. The record is 129.2 mm (5.1 in) in 1939, marked on the chart; the median year is 67.3 mm (2.6 in).
Wettest five days (Rx5day) at Ottawa Cda by year
Year
Wettest five days (Rx5day)
1889
36.1 mm (1.4 in)
1890
54.1 mm (2.1 in)
1891
73.3 mm (2.9 in)
1892
62.7 mm (2.5 in)
1893
110.0 mm (4.3 in)
1894
74.3 mm (2.9 in)
1895
82.5 mm (3.2 in)
1896
69.0 mm (2.7 in)
1897
49.1 mm (1.9 in)
1898
63.5 mm (2.5 in)
1899
128.8 mm (5.1 in)
1900
72.1 mm (2.8 in)
1901
73.7 mm (2.9 in)
1902
74.2 mm (2.9 in)
1903
70.1 mm (2.8 in)
1904
52.7 mm (2.1 in)
1905
66.3 mm (2.6 in)
1906
62.5 mm (2.5 in)
1907
76.7 mm (3.0 in)
1908
54.8 mm (2.2 in)
1909
58.6 mm (2.3 in)
1910
57.9 mm (2.3 in)
1911
49.3 mm (1.9 in)
1912
57.1 mm (2.2 in)
1913
59.2 mm (2.3 in)
1914
51.4 mm (2.0 in)
1915
70.4 mm (2.8 in)
1916
94.9 mm (3.7 in)
1917
48.5 mm (1.9 in)
1918
68.6 mm (2.7 in)
1919
54.2 mm (2.1 in)
1920
58.4 mm (2.3 in)
1921
82.0 mm (3.2 in)
1922
57.2 mm (2.3 in)
1923
69.3 mm (2.7 in)
1924
70.1 mm (2.8 in)
1925
73.2 mm (2.9 in)
1926
85.1 mm (3.4 in)
1927
76.2 mm (3.0 in)
1928
113.3 mm (4.5 in)
1929
63.8 mm (2.5 in)
1930
58.9 mm (2.3 in)
1931
46.7 mm (1.8 in)
1932
67.3 mm (2.6 in)
1933
80.8 mm (3.2 in)
1934
82.6 mm (3.3 in)
1935
75.4 mm (3.0 in)
1936
53.8 mm (2.1 in)
1937
70.8 mm (2.8 in)
1938
72.1 mm (2.8 in)
1939
129.2 mm (5.1 in)
1940
56.9 mm (2.2 in)
1941
77.9 mm (3.1 in)
1942
99.5 mm (3.9 in)
1943
104.4 mm (4.1 in)
1944
46.3 mm (1.8 in)
1945
77.5 mm (3.1 in)
1946
88.7 mm (3.5 in)
1947
68.2 mm (2.7 in)
1948
64.5 mm (2.5 in)
1949
69.6 mm (2.7 in)
1950
85.9 mm (3.4 in)
1951
45.7 mm (1.8 in)
1952
74.7 mm (2.9 in)
1953
60.0 mm (2.4 in)
1954
59.2 mm (2.3 in)
1955
67.3 mm (2.6 in)
1956
56.7 mm (2.2 in)
1957
58.0 mm (2.3 in)
1958
58.4 mm (2.3 in)
1959
50.6 mm (2.0 in)
1960
52.3 mm (2.1 in)
1961
49.5 mm (1.9 in)
1962
50.4 mm (2.0 in)
1963
67.1 mm (2.6 in)
1964
49.6 mm (2.0 in)
1965
82.3 mm (3.2 in)
1966
53.6 mm (2.1 in)
1967
71.7 mm (2.8 in)
1968
58.7 mm (2.3 in)
1969
82.6 mm (3.3 in)
1970
67.3 mm (2.6 in)
1971
71.1 mm (2.8 in)
1972
97.2 mm (3.8 in)
1973
85.9 mm (3.4 in)
1974
54.9 mm (2.2 in)
1975
53.6 mm (2.1 in)
1976
80.8 mm (3.2 in)
1977
60.8 mm (2.4 in)
1978
49.4 mm (1.9 in)
1979
57.2 mm (2.3 in)
1980
55.8 mm (2.2 in)
1981
77.2 mm (3.0 in)
1982
59.6 mm (2.3 in)
1983
83.8 mm (3.3 in)
Longest dry spell (CDD)
The longest dry spell of the year at Ottawa Cda, 1889 to 1983. The record is 36 days in 1961, marked on the chart; the median year is 15 days.
Longest dry spell (CDD) at Ottawa Cda by year
Year
Longest dry spell (CDD)
1889
9 days
1890
16 days
1891
11 days
1892
22 days
1893
11 days
1894
18 days
1895
20 days
1896
12 days
1897
11 days
1898
16 days
1899
17 days
1900
19 days
1901
11 days
1902
13 days
1903
17 days
1904
16 days
1905
14 days
1906
12 days
1907
11 days
1908
13 days
1909
14 days
1910
12 days
1911
14 days
1912
18 days
1913
14 days
1914
19 days
1915
17 days
1916
16 days
1917
18 days
1918
13 days
1919
15 days
1920
11 days
1921
14 days
1922
18 days
1923
14 days
1924
16 days
1925
13 days
1926
9 days
1927
16 days
1928
14 days
1929
13 days
1930
18 days
1931
13 days
1932
15 days
1933
13 days
1934
19 days
1935
17 days
1936
15 days
1937
13 days
1938
11 days
1939
22 days
1940
13 days
1941
26 days
1942
15 days
1943
13 days
1944
19 days
1945
14 days
1946
10 days
1947
21 days
1948
16 days
1949
15 days
1950
14 days
1951
12 days
1952
18 days
1953
12 days
1954
15 days
1955
16 days
1956
16 days
1957
15 days
1958
15 days
1959
15 days
1960
18 days
1961
36 days
1962
14 days
1963
19 days
1964
16 days
1965
19 days
1966
11 days
1967
18 days
1968
17 days
1969
17 days
1970
18 days
1971
12 days
1972
13 days
1973
11 days
1974
12 days
1975
16 days
1976
19 days
1977
14 days
1978
35 days
1979
22 days
1980
14 days
1981
8 days
1982
13 days
1983
13 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
93 years with a frost
Across 93 years with a frost, the median last spring frost at Ottawa Cda falls on 10 May and the median first autumn frost on 29 September, which leaves a median of 142 days between them.
In 1954 to 1983 the median growing season was 145 days. That is 7 days fewer than in 1890 to 1920.
Fitted over all years, the growing season changes by -0.3 days per decade at this station.
Frost dates and growing season at Ottawa Cda
Measure
Median, all years
Earliest period (1890 to 1920)
Recent period (1954 to 1983)
Recent against earliest
Fitted trend
Last spring frost
10 May
4 May
6 May
2 days later
0.0 days per decade
First autumn frost
29 September
1 October
1 October
no change
-0.3 days per decade
Growing days
142 days
152 days
145 days
7 days fewer
-0.3 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
94 years, 1890 to 1983
A day with at least 43.2 mm (1.7 in) of rain is expected about once in 2 years. A day with at least 91.3 mm (3.6 in) of rain is expected about once in 100 years.
Rainfall return levels at Ottawa Cda: the daily rain expected about once in a given number of years
Expected about once in
A day with at least
Note
2 years
43.2 mm (1.7 in)
5 years
55.3 mm (2.2 in)
10 years
63.6 mm (2.5 in)
25 years
74.5 mm (2.9 in)
50 years
82.8 mm (3.3 in)
100 years
91.3 mm (3.6 in)
Longer than the 94 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, 94 years of values from 1890 to 1983.
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: 93.2 mm (3.7 in) in 1942; 90.4 mm (3.6 in) in 1943; 77.5 mm (3.1 in) in 1946.
Station Changes
1 suspected
One change was suspected in the annual mean temperature of Ottawa Cda, at 1948. Each is measured against neighbouring stations.
Relative to 5 neighbouring stations, the station's annual mean temperature from 1948 ran 0.3 C (0.5 F) higher than in the years before (likely change).
Suspected changes in the annual mean temperature at Ottawa Cda, against neighbouring stations
Year
Shift (C)
Shift (F)
Strength
Neighbours
1948
+0.3
+0.5
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
Data for Ottawa Cda standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Ottawa Cda threshold days by year: CSV or JSON. Field meanings are on the data page.
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 2026-10-16 (16 October 2026). Records are computed by this site and are not official.