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2018 North American heat wave

Weather event in North America

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Through Canada, Atmospheric temperature and Montreal

Canada

Quebec and Ontario

From June 29 to July 6, 2018, the air temperature consistently rose above 35 °C (95.0 °F) in parts of Quebec and Ontario. The humidex value for Ottawa on Canada Day between noon and 3 pm was 47.0 °C (116.6 °F), the highest ever recorded in the city. The humidex also peaked at 46.0 °C (114.8 °F) in Toronto and 45 °C (113 °F) in Montreal. The heat wave also affected the Maritimes, with the humidex value reaching 35 °C (95 °F) in Halifax and 45 °C (113 °F) at Greenwood in the Annapolis Valley, on 5 July.

On 4 July, Montreal emergency services reported twelve hundred calls per day about the heat, up 30% from prior busiest days.

As of 10 July, seventy-four people, most of them already ill, had died heat-related deaths in Quebec. This province's death toll is reported as much higher than others' because of its looser rules for attributing death to heat. In Ontario, where only accidental deaths directly caused by heat are counted, the coroner's office is investigating three possible cases.

Maritime provinces

While the heat wave ended on 10 July in Central Canada, this was not so for the Maritimes. On the 23rd of July, the interaction between a far-northwest Azores-Bermuda High and a trough over Ontario led to the issuing of heat warnings for all three Maritime Provinces, with several locations reporting humidex values in excess of 36. In Halifax, the heat wave contributed to a record-breaking number of hot days in July, with the airport reporting daily high temperatures in excess of 25 °C on twenty-two days that month, breaking the previous record of twenty-one days set in 2008, 2003, and 1924.

Western Canada

British Columbia

On 8 and 9 August, temperatures reached high levels in Metro Vancouver. The daily highs in Abbotsford were 35.6 °C (96.1 °F) and 34.1 °C (93.4 °F) respectively. Temperatures on the waterfront of Vancouver reached 31.0 °C (87.8 °F) and 30.8 °C (87.4 °F). The hottest temperature reached in the Lower Mainland was 36.5 °C (97.7 °F) in Cultus Lake. Cranbrook broke its record for August of 37.2 °C (99.0 °F), and the all-time record of 38.9 °C (102.0 °F), with temperatures reaching 40.5 °C (104.9 °F). Creston broke its August record of 38.0 °C (100.4 °F), reaching 38.7 °C (101.7 °F), but did not break the all-time record.

Alberta

The largest city to break an all-time record was Calgary, with temperatures reaching 36.7 °C (98.1 °F). The previous record for August was 35.6 °C (96.1 °F), while the all-time record was 36.1 °C (97.0 °F). Temperatures in Lethbridge reached 40.5 °C (104.9 °F), breaking the previous August record of 38.9 °C (102.0 °F), and surpassing its all-time record of 40.0 °C (104.0 °F). Medicine Hat reached 40.4 °C (104.7 °F), the highest recorded temperature since 1969. Barnwell recorded the highest temperature of 40.8 °C (105.4 °F) during the heat wave on August 10.

Saskatchewan

The core heat passed over Saskatchewan on August 10 and 11. Numerous temperature readings above 40 °C (104 °F) were recorded across the province including in Assiniboia and Swift Current, which both recorded 2 consecutive days with high temperatures above 40 °C (104 °F). This was the first time maximum temperatures greater than 40 °C (104 °F) were recorded since 2003. Numerous monthly records were set including in Moose Jaw, where the temperature reached 42.3 °C (108.1 °F), and Regina where the maximum temperature was 41.3 °C (106.3 °F).

Manitoba

Numerous daily records were set across Manitoba on August 11 and 12. High temperatures of 40.0 °C (104.0 °F) were recorded on Manitoba Agriculture weather stations in both Elm Creek and Waskada on August 12. These were the first 40 °C (104 °F) readings in Manitoba since 1989. Melita recorded three consecutive days with temperatures above 35.0 °C (95.0 °F) from August 10–12, peaking at 39.6 °C (103.3 °F) on August 12. On August 12 in Winnipeg, temperatures peaked at 37.5 °C (99.5 °F), the warmest temperature since 1995, with the humidex reaching 45.0 °C (113.0 °F), the third highest August humidex on record.

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