Climate Trends in Canada

• In Canada, the longest run of hot days in a row in the data is 19 days, at Waneta (Canada), from 22 July 1951 to 9 August 1951.
• In Canada, the longest run of days in a row at or above 40 C in the data is 5 days, at Waneta (Canada), from 30 June 1924 to 4 July 1924.
• In Canada, the longest run of frost days in a row in the data is 345 days, at Isachsen (Canada), from 21 August 1960 to 31 July 1961.
• In Canada, the longest run of ice days in a row in the data is 293 days, at Alert (Canada), from 25 August 1956 to 13 June 1957.
• In Canada, the longest run of dry days in a row in the data is 251 days, at Arctic Bay (Canada), in 1950.
• In Canada, the longest run of wet days in a row in the data is 52 days, at Estevan Point (Canada), in 1963.
• In Canada, the longest run of longest run of nights at or above 25 c in the data is 9 days, at Ruel (Canada), from 28 May 1919 to 5 June 1919.

Longest run of days at or above 35 C

Consecutive days with a daily maximum at or above 35 C (95 F).

Longest run of days at or above 40 C

Consecutive days with a daily maximum at or above 40 C (104 F).

Longest run of frost days (minimum at or below 0 C)

Consecutive days with a daily minimum at or below 0 C (32 F).

Longest run of ice days (maximum at or below 0 C)

Consecutive days with a daily maximum at or below 0 C (32 F).

Longest dry spell (days under 1 mm of rain), within one year

Consecutive days with less than 1 mm (0.04 in) of rain, the longest run within a year. The dates are not kept, so the list gives the year (within the year).

Longest wet spell (days with 1 mm or more of rain), within one year

Consecutive days with 1 mm (0.04 in) or more of rain, the longest run within a year. The dates are not kept, so the list gives the year (within the year).

Longest run of nights at or above 25 C

A run belongs to the year it started in, even when it ran on into the next year. A station appears once per list, with its longest run in a complete year. Dry and wet spells are the longest run within a year. Lists use complete years only, so a long run in a year with gaps in the record is not counted.

• In Canada, the largest reported one day rise in the daily maximum is 44.4 C (79.9 F), at Entrance (Canada) on 25 February 1957.
• In Canada, the largest reported one day drop in the daily maximum is 38.8 C (69.8 F), at Pelly Ranch (Canada) on 8 December 1964.
• In Canada, the largest reported one day rise in the daily minimum is 45.0 C (81.0 F), at Fort McPherson (Canada) on 28 December 1927.
• In Canada, the largest reported one day drop in the daily minimum is 40.0 C (72.0 F), at Maniwaki 2 (Canada) on 2 January 1918.
• In Canada, the largest reported widest range between the high and the low of one day is 49.5 C (89.1 F), at Barrage Gouin (Canada) on 25 January 1950.

Caveat.Single readings can still be instrument errors that quality control missed. A station with one faulty value can top a list, so read each entry as a reported value, not as a confirmed event.

Biggest one day rise in the daily maximum

The largest increase in the daily maximum temperature from one day to the next. Values are in degrees Celsius with Fahrenheit beside them.

Biggest one day drop in the daily maximum

The largest decrease in the daily maximum temperature from one day to the next. Values are in degrees Celsius with Fahrenheit beside them.

Biggest one day rise in the daily minimum

The largest increase in the daily minimum temperature from one day to the next. Values are in degrees Celsius with Fahrenheit beside them.

Biggest one day drop in the daily minimum

The largest decrease in the daily minimum temperature from one day to the next. Values are in degrees Celsius with Fahrenheit beside them.

Widest range between the high and the low of one day

The largest difference between the highest and the lowest temperature of the same day. Values are in degrees Celsius with Fahrenheit beside them.

Only stations with at least 10 complete years are listed, and a station appears once per list.

• In Canada, the share of stations with a hot and dry summer is shown for each year from 1883 to 1983, for 626 stations with at least 20 complete summers in 1961-1990. Each year counts the stations of that set with a complete summer in the year.
• In Canada, 9.5% of station summers in 1961-1990 were hot and dry (13,808 station summers).
• In Canada, 8.6% of station summers in 1969-1983 were hot and dry (9,179 station summers).
• In Canada, 1894 had the highest share: 66.7% of 24 stations (16).

A summer is hot when its mean daily maximum is at or above the station's 80th percentile of its 1961-1990 summers, and dry when its rain is at or below the 20th percentile. A summer is hot and dry when it is both. Summer is June to August north of the equator and December to February south of it, labelled by the year of its first month.

Share of stations with a hot and dry summer

The ten most extreme station summers

Ranked by the temperature z score minus the rain z score against the station's own 1961-1990 mean and standard deviation (at least 0.3 C and 5 mm). A summer is labelled by the year of its first month.