News Release

Ontario Weather Review

May 2009

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.

Severe Weather

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
PickleLake	4.4	9.3	-4.9	2002
Kenora	7.4	11.8	-4.4	2004
Dryden	7.2	11.2	-4.0	2004
RedLake	6.1	10.0	-3.9	2004
Sioux Lookout	6.9	10.5	-3.6	2004
Kapuskasing	6.3	9.0	-2.7	1997
Geraldton	6.1	8.5	-2.4	2008
Timmins	7.5	9.6	-2.1	2004
Chapleau	7.3	9.4	-2.1	2008
Kingston	11.3	13.3	-2.0	2002
Earlton	8.5	10.5	-2.0	2002
Unusual precipitation readings (in millimetres):
Location	Precipitation	Normal	Difference	Wettest since
RedLake	109.6	54.6	55.0	2007
Dryden	119.5	67.2	52.3	2004
Sioux Lookout	111.0	64.4	46.6	2007
PickleLake	102.8	60.3	42.5	2006
Moosonee	95.5	53.7	41.8	2008
Trenton	104.9	71.6	33.3	2008
North Bay	119.6	87.6	32	2008
Chapleau	101	72.7	28.3	2008
Sault Ste. Marie	90.2	63.1	27.1	2004
Wawa	99.6	74.2	25.4	2004
Record snowfall readings (in centimetres):
Location	Snowfall	Normal	Difference	Previous record
PickleLake	54.2	6.8	47.4	49.6 (2002)
Record precipitation ( in millimetres):
Location	Precipitation	Normal	Difference	Previous record
Peterborough	158.5	73.2	85.3	131.2 (2002)

 

Media: For more information, please contact:

Jack Saunders
Communications Advisor/Media Relations
Environment Canada – Ontario
(416) 739-4785