Record envelope, standing records and threshold days for Yellowknife Hydro (CA002204200), Northwest Territories, Canada, with 58 years of record.
Key Facts for Yellowknife Hydro
Yellowknife Hydro (CA002204200) is a weather station in Northwest Territories, Canada at 62.67 latitude and -114.25 longitude, 159 m (522 ft) above sea level.
The station reports from 1943 to 2000, 58 years of record.
1,464 records set at Yellowknife Hydro still stand.
Records are tracked for tmax, tmin, prcp, snow: an element needs 30 years of data to be eligible.
Yellowknife Hydro set a daily record high minimum temperature of -17.0 C (1.4 F) on 25 December 1983.
Record highRecord low2026 daily maximum2026 daily minimum
The band shows the record high and record low for each calendar day at Yellowknife Hydro. 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 Yellowknife Hydro, with 2026 drawn through them
Month
Highest record high
Lowest record low
2026 highest maximum
2026 lowest minimum
Jan
2.8 C (37.0 F)
-53.9 C (-65.0 F)
n/a
n/a
Feb
6.7 C (44.1 F)
-53.9 C (-65.0 F)
n/a
n/a
Mar
12.8 C (55.0 F)
-46.7 C (-52.1 F)
n/a
n/a
Apr
21.0 C (69.8 F)
-43.3 C (-45.9 F)
n/a
n/a
May
25.6 C (78.1 F)
-26.1 C (-15.0 F)
n/a
n/a
Jun
30.6 C (87.1 F)
-6.1 C (21.0 F)
n/a
n/a
Jul
32.2 C (90.0 F)
-1.1 C (30.0 F)
n/a
n/a
Aug
30.6 C (87.1 F)
-3.9 C (25.0 F)
n/a
n/a
Sep
26.7 C (80.1 F)
-13.3 C (8.1 F)
n/a
n/a
Oct
17.2 C (63.0 F)
-27.2 C (-17.0 F)
n/a
n/a
Nov
7.2 C (45.0 F)
-45.6 C (-50.1 F)
n/a
n/a
Dec
1.7 C (35.1 F)
-47.2 C (-53.0 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at Yellowknife Hydro still stand. 1966 holds the most, with 77.
Standing records at Yellowknife Hydro by the year they were set
Year set
Standing records
1943
38
1944
47
1945
25
1946
37
1947
47
1948
46
1949
25
1950
40
1951
48
1952
32
1953
49
1954
39
1955
41
1956
40
1957
31
1958
20
1959
65
1960
18
1961
59
1962
26
1963
30
1964
21
1965
40
1966
77
1967
41
1968
34
1969
37
1970
25
1972
36
1973
30
1974
28
1975
26
1976
26
1977
24
1978
12
1979
41
1980
40
1981
52
1982
27
1983
44
All-Time Record Progression
1 new records
1 all-time records were set at Yellowknife Hydro between 11 July 1975 and 11 July 1975. Each dot is a new record.
When Yellowknife Hydro set new all-time records
Date
Kind
Detail
1975-07-11
Record high maximum temperature
Record high maximum temperature 32.2 C (90.0 F)
Wettest Day of Each Month
Oct: 42.7 mm (1.7 in)
The wettest day on record for each calendar month at Yellowknife Hydro. The most was 42.7 mm (1.7 in) on 11 October 1967.
Record daily precipitation for each month at Yellowknife Hydro
Month
Record daily precipitation (mm)
Date
Jan
9.4 mm (0.37 in)
16 January 1968
Feb
10.4 mm (0.4 in)
8 February 1976
Mar
20.3 mm (0.8 in)
16 March 1972
Apr
15.2 mm (0.6 in)
18 April 1964
May
21.3 mm (0.8 in)
27 May 1956
Jun
31.5 mm (1.2 in)
1 June 1976
Jul
30.5 mm (1.2 in)
21 July 1961
Aug
32.8 mm (1.3 in)
29 August 1975
Sep
32.2 mm (1.3 in)
7 September 1982
Oct
42.7 mm (1.7 in)
11 October 1967
Nov
14.0 mm (0.6 in)
23 November 1967
Dec
21.6 mm (0.9 in)
31 December 1958
Period of Record Coverage
1943 to 1983
Complete yearUnder 90 percent of days
40 years of record at Yellowknife Hydro, 1943 to 1983. 4 years have data for under 90 percent of days and are left out of rankings: 1964, 1976, 1977, 1978.
Cooler than the station meanWarmer than the station mean
One stripe for each of 30 complete years at Yellowknife Hydro, 1943 to 1983. Blue stripes are years cooler than the station's own mean of -6.1 C (20.9 F); red stripes are warmer. The coolest year was 1961, at -7.9 C (17.7 F), and the warmest was 1953, at -3.9 C (25.1 F). The strongest colour marks a difference of 2.3 C (4.1 F).
Annual mean temperature at Yellowknife Hydro as warming stripes, 1943 to 1983
Year
Annual mean temperature
Difference from the station mean
1943
-5.3 C
+0.88 C
1944
-4.4 C
+1.77 C
1945
-6.5 C
-0.36 C
1946
-7.0 C
-0.83 C
1947
-7.2 C
-1.08 C
1948
-6.9 C
-0.75 C
1950
-7.8 C
-1.67 C
1951
-7.2 C
-1.06 C
1952
-4.5 C
+1.65 C
1953
-3.9 C
+2.28 C
1954
-5.6 C
+0.56 C
1955
-6.5 C
-0.39 C
1956
-6.7 C
-0.60 C
1957
-6.4 C
-0.29 C
1958
-5.5 C
+0.59 C
1959
-7.7 C
-1.57 C
1960
-6.3 C
-0.15 C
1961
-7.9 C
-1.79 C
1962
-6.7 C
-0.56 C
1963
-5.8 C
+0.34 C
1965
-7.4 C
-1.30 C
1967
-6.6 C
-0.44 C
1968
-6.1 C
-0.01 C
1969
-5.2 C
+0.92 C
1970
-5.4 C
+0.69 C
1973
-4.6 C
+1.58 C
1974
-6.6 C
-0.44 C
1979
-5.9 C
+0.23 C
1980
-4.7 C
+1.45 C
1983
-5.8 C
+0.38 C
The fitted trend in annual mean temperature here over 1943 to 1983 is 0.2 C (-0.2 to 0.5) per decade. The interval includes zero, so the trend is not clearly different from zero. In Fahrenheit: 0.3 F (-0.4 to 0.9) per decade. The slope is a straight line fitted to 30 complete years; the brackets give its 95 percent interval.
Fitted temperature trends per decade at Yellowknife Hydro
Measure
Per decade (C)
Per decade (F)
Period
Complete years
Reading
Annual mean temperature
0.2 C (-0.2 to 0.5) per decade
0.3 F (-0.4 to 0.9) per decade
1943 to 1983
30
Not clearly different from zero
Mean daily maximum
0.1 C (-0.2 to 0.4) per decade
0.1 F (-0.4 to 0.7) per decade
1943 to 1983
30
Not clearly different from zero
Mean daily minimum
0.2 C (-0.2 to 0.7) per decade
0.4 F (-0.4 to 1.2) per decade
1943 to 1983
30
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
1943 to 1983
Yearly extremes at Yellowknife Hydro: the record and the median year
Measure
Record
Year of the record
Median year
Years with a value
Hottest day (TXx)
32.2 C (90.0 F)
1975
28.9 C (84.0 F)
40
Coldest night (TNn)
-53.9 C (-65.0 F)
1947
-46.7 C (-52.1 F)
40
Wettest day (Rx1day)
42.7 mm (1.7 in)
1967
20.3 mm (0.8 in)
40
Wettest five days (Rx5day)
65.0 mm (2.6 in)
1967
32.4 mm (1.3 in)
40
Longest dry spell (CDD)
66 days
1944
32 days
40
Hottest day (TXx)
The hottest day of the year at Yellowknife Hydro, 1943 to 1983. The record is 32.2 C (90.0 F) in 1975, marked on the chart; the median year is 28.9 C (84.0 F).
Hottest day (TXx) at Yellowknife Hydro by year
Year
Hottest day (TXx)
1943
27.2 C (81.0 F)
1944
30.6 C (87.1 F)
1945
30.6 C (87.1 F)
1946
28.3 C (82.9 F)
1947
29.4 C (84.9 F)
1948
30.0 C (86.0 F)
1949
26.1 C (79.0 F)
1950
29.4 C (84.9 F)
1951
30.0 C (86.0 F)
1952
26.1 C (79.0 F)
1953
30.0 C (86.0 F)
1954
28.9 C (84.0 F)
1955
30.6 C (87.1 F)
1956
28.9 C (84.0 F)
1957
27.8 C (82.0 F)
1958
26.1 C (79.0 F)
1959
28.9 C (84.0 F)
1960
28.9 C (84.0 F)
1961
31.1 C (88.0 F)
1962
28.9 C (84.0 F)
1963
26.7 C (80.1 F)
1964
31.7 C (89.1 F)
1965
26.7 C (80.1 F)
1966
29.4 C (84.9 F)
1967
28.9 C (84.0 F)
1968
25.0 C (77.0 F)
1969
27.8 C (82.0 F)
1970
29.4 C (84.9 F)
1972
28.9 C (84.0 F)
1973
30.0 C (86.0 F)
1974
28.3 C (82.9 F)
1975
32.2 C (90.0 F)
1976
27.8 C (82.0 F)
1977
26.7 C (80.1 F)
1978
25.6 C (78.1 F)
1979
30.0 C (86.0 F)
1980
28.0 C (82.4 F)
1981
29.5 C (85.1 F)
1982
30.5 C (86.9 F)
1983
29.0 C (84.2 F)
Coldest night (TNn)
The coldest night of the year at Yellowknife Hydro, 1943 to 1983. The record is -53.9 C (-65.0 F) in 1947, marked on the chart; the median year is -46.7 C (-52.1 F).
Coldest night (TNn) at Yellowknife Hydro by year
Year
Coldest night (TNn)
1943
-46.1 C (-51.0 F)
1944
-43.3 C (-45.9 F)
1945
-44.4 C (-47.9 F)
1946
-48.9 C (-56.0 F)
1947
-53.9 C (-65.0 F)
1948
-47.2 C (-53.0 F)
1949
-46.1 C (-51.0 F)
1950
-50.0 C (-58.0 F)
1951
-47.2 C (-53.0 F)
1952
-48.9 C (-56.0 F)
1953
-46.1 C (-51.0 F)
1954
-47.2 C (-53.0 F)
1955
-46.7 C (-52.1 F)
1956
-46.1 C (-51.0 F)
1957
-48.3 C (-54.9 F)
1958
-46.7 C (-52.1 F)
1959
-47.8 C (-54.0 F)
1960
-50.0 C (-58.0 F)
1961
-46.1 C (-51.0 F)
1962
-47.8 C (-54.0 F)
1963
-48.3 C (-54.9 F)
1964
-43.9 C (-47.0 F)
1965
-47.2 C (-53.0 F)
1966
-48.9 C (-56.0 F)
1967
-46.7 C (-52.1 F)
1968
-49.4 C (-56.9 F)
1969
-46.1 C (-51.0 F)
1970
-45.6 C (-50.1 F)
1972
-45.0 C (-49.0 F)
1973
-48.3 C (-54.9 F)
1974
-48.3 C (-54.9 F)
1975
-46.7 C (-52.1 F)
1976
-43.3 C (-45.9 F)
1977
-45.0 C (-49.0 F)
1978
-42.2 C (-44.0 F)
1979
-47.8 C (-54.0 F)
1980
-45.0 C (-49.0 F)
1981
-43.5 C (-46.3 F)
1982
-48.0 C (-54.4 F)
1983
-45.0 C (-49.0 F)
Wettest day (Rx1day)
The wettest day of the year at Yellowknife Hydro, 1943 to 1983. The record is 42.7 mm (1.7 in) in 1967, marked on the chart; the median year is 20.3 mm (0.8 in).
Wettest day (Rx1day) at Yellowknife Hydro by year
Year
Wettest day (Rx1day)
1943
11.2 mm (0.4 in)
1944
23.6 mm (0.9 in)
1945
7.6 mm (0.30 in)
1946
26.2 mm (1.0 in)
1947
20.3 mm (0.8 in)
1948
25.1 mm (1.0 in)
1949
10.4 mm (0.4 in)
1950
16.0 mm (0.6 in)
1951
16.0 mm (0.6 in)
1952
21.8 mm (0.9 in)
1953
16.8 mm (0.7 in)
1954
28.2 mm (1.1 in)
1955
16.8 mm (0.7 in)
1956
21.3 mm (0.8 in)
1957
29.0 mm (1.1 in)
1958
27.2 mm (1.1 in)
1959
19.8 mm (0.8 in)
1960
18.8 mm (0.7 in)
1961
30.5 mm (1.2 in)
1962
14.5 mm (0.6 in)
1963
26.4 mm (1.0 in)
1964
15.2 mm (0.6 in)
1965
19.3 mm (0.8 in)
1966
12.7 mm (0.5 in)
1967
42.7 mm (1.7 in)
1968
18.8 mm (0.7 in)
1969
20.8 mm (0.8 in)
1970
28.2 mm (1.1 in)
1972
20.3 mm (0.8 in)
1973
27.4 mm (1.1 in)
1974
26.4 mm (1.0 in)
1975
32.8 mm (1.3 in)
1976
31.5 mm (1.2 in)
1977
15.7 mm (0.6 in)
1978
16.5 mm (0.6 in)
1979
17.8 mm (0.7 in)
1980
18.0 mm (0.7 in)
1981
20.0 mm (0.8 in)
1982
32.2 mm (1.3 in)
1983
25.8 mm (1.0 in)
Wettest five days (Rx5day)
The wettest five days of the year at Yellowknife Hydro, 1943 to 1983. The record is 65.0 mm (2.6 in) in 1967, marked on the chart; the median year is 32.4 mm (1.3 in).
Wettest five days (Rx5day) at Yellowknife Hydro by year
Year
Wettest five days (Rx5day)
1943
13.9 mm (0.5 in)
1944
24.9 mm (1.0 in)
1945
18.3 mm (0.7 in)
1946
29.6 mm (1.2 in)
1947
21.8 mm (0.9 in)
1948
34.3 mm (1.4 in)
1949
19.1 mm (0.8 in)
1950
21.6 mm (0.9 in)
1951
33.3 mm (1.3 in)
1952
58.3 mm (2.3 in)
1953
38.9 mm (1.5 in)
1954
30.7 mm (1.2 in)
1955
23.9 mm (0.9 in)
1956
32.7 mm (1.3 in)
1957
37.6 mm (1.5 in)
1958
40.6 mm (1.6 in)
1959
50.0 mm (2.0 in)
1960
31.3 mm (1.2 in)
1961
41.7 mm (1.6 in)
1962
28.9 mm (1.1 in)
1963
37.1 mm (1.5 in)
1964
16.0 mm (0.6 in)
1965
26.4 mm (1.0 in)
1966
19.3 mm (0.8 in)
1967
65.0 mm (2.6 in)
1968
41.9 mm (1.6 in)
1969
48.0 mm (1.9 in)
1970
45.0 mm (1.8 in)
1972
22.9 mm (0.9 in)
1973
58.7 mm (2.3 in)
1974
33.3 mm (1.3 in)
1975
44.3 mm (1.7 in)
1976
32.5 mm (1.3 in)
1977
26.2 mm (1.0 in)
1978
25.5 mm (1.0 in)
1979
28.1 mm (1.1 in)
1980
30.7 mm (1.2 in)
1981
32.2 mm (1.3 in)
1982
48.2 mm (1.9 in)
1983
56.7 mm (2.2 in)
Longest dry spell (CDD)
The longest dry spell of the year at Yellowknife Hydro, 1943 to 1983. The record is 66 days in 1944, marked on the chart; the median year is 32 days.
Longest dry spell (CDD) at Yellowknife Hydro by year
Year
Longest dry spell (CDD)
1943
31 days
1944
66 days
1945
36 days
1946
33 days
1947
34 days
1948
65 days
1949
27 days
1950
31 days
1951
32 days
1952
41 days
1953
44 days
1954
35 days
1955
24 days
1956
50 days
1957
31 days
1958
31 days
1959
23 days
1960
21 days
1961
21 days
1962
49 days
1963
39 days
1964
30 days
1965
61 days
1966
17 days
1967
24 days
1968
33 days
1969
27 days
1970
25 days
1972
43 days
1973
38 days
1974
21 days
1975
36 days
1976
17 days
1977
18 days
1978
28 days
1979
21 days
1980
42 days
1981
34 days
1982
35 days
1983
24 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
30 years with a frost
Across 30 years with a frost, the median last spring frost at Yellowknife Hydro falls on 12 June and the median first autumn frost on 26 August, which leaves a median of 72 days between them.
Fitted over all years, the growing season changes by -0.8 days per decade at this station.
Frost dates and growing season at Yellowknife Hydro
Measure
Median, all years
Earliest period
Recent period (1943 to 1983)
Recent against earliest
Fitted trend
Last spring frost
12 June
n/a
12 June
n/a
-0.3 days per decade
First autumn frost
26 August
n/a
26 August
n/a
-1.2 days per decade
Growing days
72 days
n/a
72 days
n/a
-0.8 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
36 years, 1943 to 1983
A day with at least 21.5 mm (0.8 in) of rain is expected about once in 2 years. A day with at least 39.9 mm (1.6 in) of rain is expected about once in 100 years.
Rainfall return levels at Yellowknife Hydro: the daily rain expected about once in a given number of years
Expected about once in
A day with at least
Note
2 years
21.5 mm (0.8 in)
5 years
27.9 mm (1.1 in)
10 years
31.5 mm (1.2 in)
25 years
35.3 mm (1.4 in)
50 years
37.8 mm (1.5 in)
Longer than the 36 years of record
100 years
39.9 mm (1.6 in)
Longer than the 36 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, 36 years of values from 1943 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: 42.7 mm (1.7 in) in 1967; 32.8 mm (1.3 in) in 1975; 32.2 mm (1.3 in) in 1982.
Download the Data
Data for Yellowknife Hydro standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Yellowknife Hydro 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 2026-10-14 (14 October 2026). Records are computed by this site and are not official.