Record highRecord low2026 daily maximum2026 daily minimum
The band shows the record high and record low for each calendar day at Ottawa Nrc. 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 Nrc, with 2026 drawn through them
Month
Highest record high
Lowest record low
2026 highest maximum
2026 lowest minimum
Jan
9.4 C (48.9 F)
-37.8 C (-36.0 F)
n/a
n/a
Feb
12.2 C (54.0 F)
-33.3 C (-27.9 F)
n/a
n/a
Mar
22.8 C (73.0 F)
-24.0 C (-11.2 F)
n/a
n/a
Apr
30.0 C (86.0 F)
-15.6 C (3.9 F)
n/a
n/a
May
32.8 C (91.0 F)
-5.6 C (21.9 F)
n/a
n/a
Jun
35.0 C (95.0 F)
1.0 C (33.8 F)
n/a
n/a
Jul
36.7 C (98.1 F)
6.1 C (43.0 F)
n/a
n/a
Aug
36.7 C (98.1 F)
2.8 C (37.0 F)
n/a
n/a
Sep
33.9 C (93.0 F)
-1.1 C (30.0 F)
n/a
n/a
Oct
26.5 C (79.7 F)
-6.7 C (19.9 F)
n/a
n/a
Nov
23.3 C (73.9 F)
-18.9 C (-2.0 F)
n/a
n/a
Dec
15.6 C (60.1 F)
-30.6 C (-23.1 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at Ottawa Nrc still stand. 1959 holds the most, with 69.
Standing records at Ottawa Nrc by the year they were set
Year set
Standing records
1951
21
1952
18
1953
57
1954
39
1955
62
1956
54
1957
54
1958
34
1959
69
1960
23
1961
40
1962
41
1963
64
1964
44
1965
54
1966
44
1967
52
1968
43
1969
27
1970
40
1971
34
1972
35
1973
39
1974
40
1975
43
1976
62
1977
42
1978
33
1979
60
1980
45
1981
58
1982
51
1983
42
Wettest Day of Each Month
Aug: 71.1 mm (2.8 in)
The wettest day on record for each calendar month at Ottawa Nrc. The most was 71.1 mm (2.8 in) on 9 August 1959.
Record daily precipitation for each month at Ottawa Nrc
Month
Record daily precipitation (mm)
Date
Jan
46.0 mm (1.8 in)
8 January 1978
Feb
43.6 mm (1.7 in)
2 February 1983
Mar
51.6 mm (2.0 in)
13 March 1977
Apr
48.8 mm (1.9 in)
15 April 1956
May
41.7 mm (1.6 in)
26 May 1956
Jun
55.1 mm (2.2 in)
7 June 1971
Jul
66.5 mm (2.6 in)
9 July 1952
Aug
71.1 mm (2.8 in)
9 August 1959
Sep
61.0 mm (2.4 in)
6 September 1958
Oct
39.9 mm (1.6 in)
23 October 1957
Nov
41.0 mm (1.6 in)
26 November 1979
Dec
38.1 mm (1.5 in)
10 December 1952
Period of Record Coverage
1951 to 1983
Complete yearUnder 90 percent of days
33 years of record at Ottawa Nrc, 1951 to 1983. 1 years have data for under 90 percent of days and are left out of rankings: 1951.
Cooler than the station meanWarmer than the station mean
One stripe for each of 32 complete years at Ottawa Nrc, 1952 to 1983. Blue stripes are years cooler than the station's own mean of 6.0 C (42.9 F); red stripes are warmer. The coolest year was 1972, at 4.7 C (40.5 F), and the warmest was 1953, at 7.9 C (46.2 F). The strongest colour marks a difference of 1.9 C (3.4 F).
Annual mean temperature at Ottawa Nrc as warming stripes, 1952 to 1983
Year
Annual mean temperature
Difference from the station mean
1952
7.1 C
+1.05 C
1953
7.9 C
+1.85 C
1954
5.9 C
-0.09 C
1955
6.6 C
+0.58 C
1956
5.5 C
-0.57 C
1957
6.8 C
+0.72 C
1958
5.6 C
-0.45 C
1959
6.5 C
+0.44 C
1960
6.7 C
+0.62 C
1961
6.4 C
+0.36 C
1962
5.6 C
-0.48 C
1963
5.3 C
-0.74 C
1964
6.4 C
+0.38 C
1965
5.4 C
-0.65 C
1966
6.0 C
-0.04 C
1967
5.5 C
-0.57 C
1968
5.6 C
-0.39 C
1969
6.1 C
+0.03 C
1970
5.7 C
-0.38 C
1971
5.6 C
-0.44 C
1972
4.7 C
-1.30 C
1973
6.7 C
+0.67 C
1974
5.5 C
-0.54 C
1975
6.7 C
+0.68 C
1976
5.1 C
-0.98 C
1977
6.2 C
+0.20 C
1978
5.5 C
-0.56 C
1979
6.3 C
+0.24 C
1980
5.5 C
-0.54 C
1981
6.9 C
+0.89 C
1982
5.9 C
-0.16 C
1983
6.2 C
+0.20 C
The fitted trend in annual mean temperature here over 1952 to 1983 is -0.2 C (-0.5 to 0.1) per decade. The interval includes zero, so the trend is not clearly different from zero. In Fahrenheit: -0.4 F (-0.8 to 0.1) per decade. The slope is a straight line fitted to 32 complete years; the brackets give its 95 percent interval.
Fitted temperature trends per decade at Ottawa Nrc
Measure
Per decade (C)
Per decade (F)
Period
Complete years
Reading
Annual mean temperature
-0.2 C (-0.5 to 0.1) per decade
-0.4 F (-0.8 to 0.1) per decade
1952 to 1983
32
Not clearly different from zero
Mean daily maximum
-0.4 C (-0.6 to -0.1) per decade
-0.6 F (-1.1 to -0.2) per decade
1952 to 1983
32
Fall
Mean daily minimum
-0.1 C (-0.3 to 0.2) per decade
-0.1 F (-0.6 to 0.4) per decade
1952 to 1983
32
Not clearly different from zero
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
1951 to 1983
Yearly extremes at Ottawa Nrc: the record and the median year
Measure
Record
Year of the record
Median year
Years with a value
Hottest day (TXx)
36.7 C (98.1 F)
1955
32.8 C (91.0 F)
33
Coldest night (TNn)
-37.8 C (-36.0 F)
1957
-29.4 C (-20.9 F)
33
Wettest day (Rx1day)
71.1 mm (2.8 in)
1959
39.6 mm (1.6 in)
33
Wettest five days (Rx5day)
97.6 mm (3.8 in)
1959
60.3 mm (2.4 in)
32
Longest dry spell (CDD)
36 days
1961
16 days
33
Hottest day (TXx)
The hottest day of the year at Ottawa Nrc, 1951 to 1983. The record is 36.7 C (98.1 F) in 1955, marked on the chart; the median year is 32.8 C (91.0 F).
Hottest day (TXx) at Ottawa Nrc by year
Year
Hottest day (TXx)
1951
15.6 C (60.1 F)
1952
32.8 C (91.0 F)
1953
35.6 C (96.1 F)
1954
31.7 C (89.1 F)
1955
36.7 C (98.1 F)
1956
33.9 C (93.0 F)
1957
33.3 C (91.9 F)
1958
31.1 C (88.0 F)
1959
34.4 C (93.9 F)
1960
32.2 C (90.0 F)
1961
31.7 C (89.1 F)
1962
33.3 C (91.9 F)
1963
35.6 C (96.1 F)
1964
35.0 C (95.0 F)
1965
32.8 C (91.0 F)
1966
33.9 C (93.0 F)
1967
30.6 C (87.1 F)
1968
32.8 C (91.0 F)
1969
32.8 C (91.0 F)
1970
33.3 C (91.9 F)
1971
32.2 C (90.0 F)
1972
31.1 C (88.0 F)
1973
32.8 C (91.0 F)
1974
31.1 C (88.0 F)
1975
36.1 C (97.0 F)
1976
32.2 C (90.0 F)
1977
34.0 C (93.2 F)
1978
34.0 C (93.2 F)
1979
32.0 C (89.6 F)
1980
32.0 C (89.6 F)
1981
33.0 C (91.4 F)
1982
34.5 C (94.1 F)
1983
32.5 C (90.5 F)
Coldest night (TNn)
The coldest night of the year at Ottawa Nrc, 1951 to 1983. The record is -37.8 C (-36.0 F) in 1957, marked on the chart; the median year is -29.4 C (-20.9 F).
Coldest night (TNn) at Ottawa Nrc by year
Year
Coldest night (TNn)
1951
-30.6 C (-23.1 F)
1952
-31.7 C (-25.1 F)
1953
-23.3 C (-9.9 F)
1954
-28.9 C (-20.0 F)
1955
-29.4 C (-20.9 F)
1956
-26.7 C (-16.1 F)
1957
-37.8 C (-36.0 F)
1958
-28.3 C (-18.9 F)
1959
-29.4 C (-20.9 F)
1960
-28.3 C (-18.9 F)
1961
-27.2 C (-17.0 F)
1962
-31.1 C (-24.0 F)
1963
-32.2 C (-26.0 F)
1964
-26.7 C (-16.1 F)
1965
-31.7 C (-25.1 F)
1966
-30.0 C (-22.0 F)
1967
-33.3 C (-27.9 F)
1968
-32.2 C (-26.0 F)
1969
-25.0 C (-13.0 F)
1970
-30.0 C (-22.0 F)
1971
-31.7 C (-25.1 F)
1972
-32.2 C (-26.0 F)
1973
-31.1 C (-24.0 F)
1974
-27.2 C (-17.0 F)
1975
-29.4 C (-20.9 F)
1976
-34.4 C (-29.9 F)
1977
-28.9 C (-20.0 F)
1978
-26.5 C (-15.7 F)
1979
-28.5 C (-19.3 F)
1980
-27.0 C (-16.6 F)
1981
-32.0 C (-25.6 F)
1982
-30.0 C (-22.0 F)
1983
-28.0 C (-18.4 F)
Wettest day (Rx1day)
The wettest day of the year at Ottawa Nrc, 1951 to 1983. The record is 71.1 mm (2.8 in) in 1959, marked on the chart; the median year is 39.6 mm (1.6 in).
Wettest day (Rx1day) at Ottawa Nrc by year
Year
Wettest day (Rx1day)
1951
21.6 mm (0.9 in)
1952
67.6 mm (2.7 in)
1953
34.8 mm (1.4 in)
1954
43.2 mm (1.7 in)
1955
32.0 mm (1.3 in)
1956
48.8 mm (1.9 in)
1957
43.7 mm (1.7 in)
1958
61.0 mm (2.4 in)
1959
71.1 mm (2.8 in)
1960
27.4 mm (1.1 in)
1961
37.1 mm (1.5 in)
1962
44.2 mm (1.7 in)
1963
55.4 mm (2.2 in)
1964
25.7 mm (1.0 in)
1965
29.0 mm (1.1 in)
1966
28.4 mm (1.1 in)
1967
36.6 mm (1.4 in)
1968
34.3 mm (1.4 in)
1969
56.9 mm (2.2 in)
1970
35.6 mm (1.4 in)
1971
55.1 mm (2.2 in)
1972
40.1 mm (1.6 in)
1973
35.3 mm (1.4 in)
1974
38.4 mm (1.5 in)
1975
32.3 mm (1.3 in)
1976
39.6 mm (1.6 in)
1977
51.6 mm (2.0 in)
1978
46.0 mm (1.8 in)
1979
41.0 mm (1.6 in)
1980
30.0 mm (1.2 in)
1981
47.8 mm (1.9 in)
1982
37.4 mm (1.5 in)
1983
45.2 mm (1.8 in)
Wettest five days (Rx5day)
The wettest five days of the year at Ottawa Nrc, 1951 to 1983. The record is 97.6 mm (3.8 in) in 1959, marked on the chart; the median year is 60.3 mm (2.4 in).
Wettest five days (Rx5day) at Ottawa Nrc by year
Year
Wettest five days (Rx5day)
1951
n/a
1952
95.2 mm (3.7 in)
1953
61.5 mm (2.4 in)
1954
61.6 mm (2.4 in)
1955
52.0 mm (2.0 in)
1956
58.0 mm (2.3 in)
1957
60.5 mm (2.4 in)
1958
81.9 mm (3.2 in)
1959
97.6 mm (3.8 in)
1960
51.3 mm (2.0 in)
1961
49.8 mm (2.0 in)
1962
53.6 mm (2.1 in)
1963
60.0 mm (2.4 in)
1964
44.2 mm (1.7 in)
1965
39.7 mm (1.6 in)
1966
54.9 mm (2.2 in)
1967
63.0 mm (2.5 in)
1968
65.8 mm (2.6 in)
1969
61.0 mm (2.4 in)
1970
51.8 mm (2.0 in)
1971
55.3 mm (2.2 in)
1972
63.8 mm (2.5 in)
1973
53.6 mm (2.1 in)
1974
59.2 mm (2.3 in)
1975
54.8 mm (2.2 in)
1976
66.0 mm (2.6 in)
1977
77.2 mm (3.0 in)
1978
51.2 mm (2.0 in)
1979
62.2 mm (2.4 in)
1980
50.2 mm (2.0 in)
1981
73.4 mm (2.9 in)
1982
61.0 mm (2.4 in)
1983
66.1 mm (2.6 in)
Longest dry spell (CDD)
The longest dry spell of the year at Ottawa Nrc, 1951 to 1983. The record is 36 days in 1961, marked on the chart; the median year is 16 days.
Longest dry spell (CDD) at Ottawa Nrc by year
Year
Longest dry spell (CDD)
1951
2 days
1952
22 days
1953
20 days
1954
12 days
1955
23 days
1956
12 days
1957
16 days
1958
20 days
1959
15 days
1960
19 days
1961
36 days
1962
19 days
1963
19 days
1964
15 days
1965
18 days
1966
11 days
1967
19 days
1968
16 days
1969
12 days
1970
19 days
1971
14 days
1972
11 days
1973
12 days
1974
14 days
1975
16 days
1976
19 days
1977
14 days
1978
25 days
1979
13 days
1980
18 days
1981
11 days
1982
11 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
32 years with a frost
Across 32 years with a frost, the median last spring frost at Ottawa Nrc falls on 6 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 +2.3 days per decade at this station.
Frost dates and growing season at Ottawa Nrc
Measure
Median, all years
Earliest period
Recent period (1954 to 1983)
Recent against earliest
Fitted trend
Last spring frost
6 May
n/a
6 May
n/a
-1.0 days per decade
First autumn frost
7 October
n/a
7 October
n/a
+1.3 days per decade
Growing days
153 days
n/a
152 days
n/a
+2.3 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
30 years, 1952 to 1983
A day with at least 40.7 mm (1.6 in) of rain is expected about once in 2 years. A day with at least 80.9 mm (3.2 in) of rain is expected about once in 100 years.
Rainfall return levels at Ottawa Nrc: the daily rain expected about once in a given number of years
Expected about once in
A day with at least
Note
2 years
40.7 mm (1.6 in)
5 years
51.7 mm (2.0 in)
10 years
58.8 mm (2.3 in)
25 years
67.8 mm (2.7 in)
50 years
74.4 mm (2.9 in)
Longer than the 30 years of record
100 years
80.9 mm (3.2 in)
Longer than the 30 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, 30 years of values from 1952 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: 71.1 mm (2.8 in) in 1959; 67.6 mm (2.7 in) in 1952; 61.0 mm (2.4 in) in 1958.
Download the Data
Data for Ottawa Nrc standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Ottawa Nrc 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.