News Release
Ontario Weather Review
June 2011
Ontarians experienced normal temperatures during the month of June 2011, with mean temperatures at most locations within the normal range. Wawa was slightly warmer-than-normal, with mean temperatures being the warmest since 2007.
During summer months, precipitation typically occurs as short intense showers. This explains the localized distribution of precipitation across the province. Locations such as Kenora, Dryden, Sioux Lookout, Timmins, Peterborough and Hamilton were drier-than-normal and each received between one-half to two-thirds of the precipitation normally expected during June. On the other hand, locations such as Chapleau, Wawa, Sudbury, Earlton, Petawawa, Ottawa, Wiarton and Sarnia were wetter-than-normal, with Sarnia receiving more than twice the amount of rainfall normally experienced in June.
Severe Weather
Northern Ontario experienced a quiet start to the thunderstorm season. There was not much storm activity in May and aside from a brief burst of activity during the first week of June, all was quiet.
Several lines of storms during the early morning hours of June 1 prompted severe thunderstorms warnings in the near North and north eastern Ontario. Warnings were also issued for other storms, off and on until June 8, throughout northern Ontario, but only a few reports of severe weather generated from these storms were received by the Weather Centre. These reports included estimated wind gusts to 100 kilometres per hour, along with pea-sized hail in the Manitoulin Island area, as well as more reports of pea-sized hail near Dryden.
In addition, there were a few large-scale storm systems that brought rain to portions of northern Ontario. An Ontario Ministry of Natural Resources rain gauge in Cold Mines near Fort Frances measured 63.7 millimetres of rain during the night of June 18, which exceeds the warning criteria of 50 millimetres in a twenty-four hour period.
In contrast to northern Ontario, southern Ontario experienced a noisy start to the thunderstorm season. Two storm systems were particularly remarkable and resulted in widespread and significant damage this month.
During the week of June 4 to 9 numerous lines of storms hit a vast part of southern Ontario, from the eastern shores of Lake Huron to the Ottawa Valley. Numerous reports were received and ranged from frequent lightning, golf ball-sized hail near Toronto and extensive straight-line wind damage from Bruce County to the border with Quebec. The winds snapped and uprooted numerous trees and knocked out power lines; so many, in fact, that Hydro One reported having to send out more crews to correct the power outages caused by this series of storms than they did during the Ice Storm of January 1998.
The second noteworthy week was June 21 to 24, when thunderstorms were experienced throughout Ontario due to a large low pressure system that tracked very slowly from Wisconsin to central Quebec. Although some straight wind damage was observed close to Leamington, most of the severe weather associated with this system was found in eastern Ontario, and particularly in the National Capital Region. The repetitive nature of the thunderstorms accompanying the system resulted in over 200 millimetres of rain falling in two days for locales where thunderstorms hit several times. Ottawa International Airport reported 90 millimetres of rain on June 24, exceeding in one day its normal rainfall for the whole month of June, which is 85 millimetres. There were many reports of flash floods, collapsed roads, fires caused by lightning and wind damage. Fortunately, there were no reports of injuries.
On the evening of June 23, as powerful storms developed in relation to that same low pressure system, loonie-sized hail was reported at Constance Bay, northeast of Ottawa. One of those cells, which formed south of Kanata and travelled across the Ottawa River to the Aylmer, Quebec area, spawned Ontario’s second tornado of 2011--a Fujita Scale Zero tornado (peak wind up to 110 kilometres per hour) near Shirley’s Bay. A Fujita Scale Zero tornado is the weakest on the Fujita Damage Scale. No damage was reported nor observed by Environment Canada’s damage survey team; however, the tornado was confirmed based on photographic evidence and videos provided by several sources, which were studied by Environment Canada.
| Unusual mean temperature readings (in °C), ranked by variation from normal: | ||||
| Location | Mean Temp | Normal | Difference | Warmest since |
| Wawa | 14.2 | 11.9 | 2.3 | 2007 |
| Unusual precipitation readings (in mm), ranked by variation from normal: | ||||
| Location | Precipitation | Normal | Difference | Driest since |
| Dryden | 61.4 | 105.1 | -43.7 | 1998 |
| Kenora | 65.2 | 107.8 | -42.6 | 2004 |
| Timmins | 49.4 | 89.4 | -40.0 | 2005 |
| Hamilton | 50.2 | 83.9 | -33.7 | 2007 |
| Sioux Lookout | 64.0 | 97.3 | -33.3 | 2003 |
| Peterborough | 51.2 | 76.7 | -25.5 | 2007 |
| Location | Precipitation | Normal | Difference | Wettest since |
| Sarnia | 173.2 | 85.6 | 87.6 | 2000 |
| Wiarton | 141.3 | 74.4 | 66.9 | 2010 |
| Chapleau | 125.8 | 76.8 | 49.0 | 2007 |
| Ottawa | 130.0 | 85.0 | 45.0 | 2002 |
| Earlton | 117.0 | 77.1 | 39.9 | 1999 |
| Wawa | 122.0 | 88.8 | 33.2 | 2007 |
| Petawawa | 110.6 | 81.3 | 29.3 | 2008 |
| Sudbury | 103.4 | 77.8 | 25.6 | 2003 |
Note: The normal period used is the 1971-2000 Climate Normals.
Media: For more information, please contact:
Laurie Thibeault
Communications Officer
Environment Canada - Ontario
905-336-4711
- Date Modified: