Environment Canada

Environment Canada

June 01, 2006 11:24 ET

Environment Canada: Ontario Weather Review

TORONTO, ONTARIO--(CCNMatthews - June 1, 2006) -

May 2006

The old chestnut, "there is nothing constant in life but change," very clearly applied to the weather in Ontario this May.

Typically, the month of May is one of change. The early part of the month normally starts off on the cool side and then warms up by the end of the month. This year, the month began warm in most areas, then alternated with cool temperatures almost weekly. The Victoria Day weekend was not only cold in many locations, it even produced a bit of unexpected snow in some locations. However, that changed markedly as the month ended on a steamy note. Numerous daily maximum temperatures were broken on May 29, 30 and 31, when the year's first smog and humidex advisories were issued.

Precipitation was the big story for Northwestern Ontario. The precipitation total for Red Lake in May exceeded 145 millimetres for the month, eclipsing its previous May record by almost 40 millimetres. Most of this fell in the last few days of the month, brought on by thunderstorm activity. There were also large rainfall amounts reported in some locations in Eastern and Southern Ontario.

On the other hand, there were some dry spots - for example, Kapuskasing, which reported well-below-normal precipitation values this month.

Severe Weather

The severe weather during the month of May reflected the contrasts experienced with the temperatures. A persistent cool air mass affected a good portion of the province during the middle part of the month. In addition to the cool temperatures, cloudy skies and periods of rain also dominated the weather picture. Ottawa alone saw 39.6 millimetres of rain fall on May 12. During the early morning hours of that same day, areas to the north of Lake Superior had to deal with freezing rain and ice pellets as temperatures dipped to the freezing mark.

The cool air mass was also an unstable one and generated some reports of funnel clouds in different parts of the province. In the Bracebridge-Port Carling area on May 16, one of these funnel clouds made contact with the ground and was classified as Ontario's first tornado of the season. This tornado was only briefly in contact with the ground and did not do any appreciable damage. It was rated as a Fujita Scale Zero tornado, with winds estimated between 90 and 120 kilometres per hour.

The final days of the month ended with a very warm and humid air mass sitting over much of Ontario - more reminiscent of July than May. In addition to prompting the issuance of the season's first smog and humidex advisories, this very warm and muggy air acted as the fuel that drove the development of a number of severe thunderstorms across portions of the province. There were reports of tree damage in a variety of areas around the province, including Dryden, Timmins, New Liskeard and the Perth area in Eastern Ontario. However, for the most part the damage was not substantial and was likely caused by strong wind gusts coming from the thunderstorms in the range of 90-100 kilometres per hour and not tornado activity.

The month literally ended with a bang in some communities across Southern Ontario as strong thunderstorms developed in advance of an approaching cold front. Lightning strikes caused local power outages and, in addition to the lightning, a few of the thunderstorms brought heavy rains and small hail to some areas.



Unusual mean temperature readings:

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Location Mean Temp Normal Difference Warmest Since
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Kapuskasing 11.9 9.0 2.9 1975
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Timmins 12.5 9.6 2.9 1982
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Wawa 10.3 8.2 2.1 1999
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Sault Ste Marie 12.3 10.0 2.3 1999
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Record precipitation readings (in millimetres):

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Location Precipitation Normal Difference Previous Record
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Red Lake 178.7 54.6 124.1 107.4 (1989)
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Unusual precipitation readings (in millimetres):

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Location Precipitation Normal Difference Driest Since
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Kapuskasing 36.9 66.3 -29.4 1984
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Location Precipitation Normal Difference Wettest Since
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Sioux Lookout 123.3 64.4 58.9 2005
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Pickle Lake 116.8 60.3 56.5 1959
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Petawawa 106.8 68.5 38.3 2004
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Thunder Bay 104.0 66.5 37.5 2005
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Ottawa 114.6 79.0 35.6 2003
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Sudbury 112.2 77.5 34.7 2004
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Windsor 115.2 80.8 34.4 2004
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Trenton 105.4 71.6 33.8 2003
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Sault Ste Marie 90.0 63.1 26.9 2004
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(Egalement offert en francais)

Contact Information

  • Environment Canada, Ontario Region
    Jack Saunders
    Communications Advisor/Media Relations
    (416) 739-4785
    www.ec.gc.ca