Ontario Weather Review - August 2004
The arrival of warm and humid air into southern Ontario late this month was too little, too late for many Ontarians. Many locations in Ontario normally experience seven to 10 days each summer when the temperature rises above the 30-degree Celsius mark. That mark has only been crossed one or two times, at best, in many locations throughout the summer. The last time we had such a cool season was back in 1992, when we felt the effects of the eruption of the Mount Pinatubo volcano in the Philippines.
August continued the cool temperatures that were experienced in June and July, with monthly values running about one to three degrees below normal. The coolest areas have been in northwestern Ontario. Geraldton reported a record low mean temperature for August of 13.2. In records kept since 1981, the August low was 13.4 in 1994. Frost has already been reported in northeastern Ontario, where temperatures in Timmins dipped to -0.1° on August 24th. Other areas have also reported frost this month, about a month earlier that normal.
August's rainfall in Ontario produced record highs and lows this month. Total rainfall at the Peterborough airport for June through August was a record 389.3 millimetres, which is the wettest ever since records were kept (1969). This three-month total eclipsed the 342.1-millimetre record set in 1980. Included in this three-month total was the 103.0-millimetre rainfall measurement during the July 14-15 flood. Observers measured readings of up to 235 millimetres in other parts of the city during this storm event. By contrast, a record low for rainfall was set in Kingston in August of 26.6 millimetres. Records have been kept for Kingston since 1961.
Unusual mean temperature readings:
Unusual total precipitation readings (in millimetres):
August was a relatively quiet month with respect to severe or damaging storms. The two main occurrences were the 11th tornado of the season, which occurred on August 10th in Burnstown, Ontario. This tornado was rated as a Fujita Scale 1 tornado (winds between 117 and 180 kilometres per hour). The second significant event was tree damage occurring in the Thunder Bay area on August 18th, after a cold frontal passage where winds briefly gusted to in excess of 80 kilometres per hour.