Ontario Weather Review
Quite a mixed bag of weather conditions was reported in May. Northern areas had very cold temperatures in some locations and many locations reported snow. The snow that fell in Pickle Lake actually broke their all-time May snowfall record – and most of it fell in just two days. Temperature-wise, the mean values were two to five degrees below normal for most of Northwestern Ontario.
The rest of the province experienced temperatures within a couple of degrees of normal, but leaning to the colder side. Precipitation totals were mixed. Portions of Southern Ontario had values below normal, which may have challenged a few gardeners trying to get a head start on the growing season. Some places received more than their fair share of rain this month, with double their typical total values. Peterborough even set a record for its monthly precipitation.
The past month was fairly quiet with respect to severe weather. May is traditionally the month where powerful thunderstorms can impact almost anywhere in the province. However, during this past month, the most significant thunderstorms stayed south of the region in the American Midwest.
A thunderstorm of note did occur during the morning hours of May 9. This thunderstorm intensified over the Halton Hills area, producing nickel-sized hail. The thunderstorm then moved eastward through portions of Brampton and the north end of Toronto, continuing to produce hail, abundant rainfall and some powerful wind gusts. Pearson Airport reported a gust of 78 kilometres per hour as the storm moved over that location. There were also some reports of local flooding and wind damage.
The month drew to a close with a couple of significant rainfall events. The first occurred in portions of northwestern Ontario during May 25 and 26, with a solid soaking for the Kenora and Dryden areas. These regions received 40 to 45 millimetres of rain between the morning of May 25 and the morning of May 26. Amounts in excess of 50 millimetres were recorded in the Atikokan area by the time the rain began to taper off there by midday on May 26. Thunder Bay and regions just to the west of Lake Superior were spared the worst of the rain as it tracked northeast from Atikokan towards Lake Nipigon.
The second significant rainfall event occurred on the heels of the one just mentioned, on May 27 and 28. Yet another slow-moving, moisture-laden weather system, this one coming up from the American Midwest, spread rain to much of southern Ontario. Some areas in the southern part of the province also experienced heavier showers and thunderstorms embedded within the general area of rain. This event resulted in two-day local rainfall totals up to the 50-millimetre mark.
|Unusual temperature readings:|
|Location||Mean Temp||Normal||Difference||Coldest since|
|Unusual precipitation readings (in millimetres):|
|Sault Ste. Marie||90.2||63.1||27.1||2004|
|Record snowfall readings (in centimetres):|
|Record precipitation ( in millimetres):|
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