News Release

Ontario Weather Review

October 2011

Thanks to the warm conditions experienced across the province, the month of October 2011 was a record-breaker in some areas of Ontario. In terms of precipitation, conditions were drier in northern Ontario and near-normal to wetter-than-normal in southern Ontario.

Mean temperature records were shattered in Chapleau, Dryden and Geraldton, with mean temperatures reaching higher-than-normal values by as much as 4.2 degrees Celsius.

While not all locations met our threshold (2 degree above-normal mean temperatures) to be considered warmer-than-normal, all sites had mean temperatures that exceeded the normal values for October.  The most impressive departures from normal values were observed in northern Ontario, where differences of up to 4.3 degrees Celsius were reported and in many cases, it was the warmest October in over forty years.

The warmer temperatures and frost-free conditions extended the growing season for farmers, which compensated for the late spring planting.  Meanwhile, backyard gardeners could enjoy their flowers and gardens for an extra month. 

Another highlight for October was the August-like temperatures that prevailed during the Thanksgiving weekend.  Single-day records were broken across the province with temperatures reaching the mid-to-high twenties.  The spectacular fall display disappeared the week following Thanksgiving, when high winds and precipitation set in.

No monthly records were broken for rainfall or total precipitation amounts, however, it was the driest October that Geraldton, Wawa, Kapuskasing and Moosonee have seen in the last few years. On the other hand, some locations in northern Ontario, such as Red Lake, Timmins and Nickle Belt were wetter-than-normal.  Southern Ontario also experienced wetter-than-normal conditions. 

Since observations began in 1947, October 2011 was the second wettest in Wiarton, with 167 millimetres of rain falling.  It received the most rain since 1954, when 180.6 millimetres of rainfall fell that month.

Severe Weather

The first full month of fall was relatively quiet across the province. As happens normally during the month, the first snowfalls occurred in various locations across northern Ontario. One of the more notable amounts was five centimetres of snow falling in Red Lake on October 16.  .

The most noteworthy storm system of the month impacted southern and central Ontario on October 19 and 20.  The system formed on October 18 over West Virginia and split into two distinct low pressure systems during the early morning hours of October 19.  One system entrenched itself over Ohio on October 19, while another became established over the Virginia coast. The system over Ohio moved very slowly and spun bands of rain northward over southern Ontario. The most intense rainfall occurred in many areas late in the day on October 19 and into the morning hours of October 20.  The storm system over Ohio finally started to push off northward late in the day on October 20, causing the rain to taper off in much of southern Ontario. The rain changed to drizzle in the North Bay and Sudbury areas by the morning of October 21.  Total rainfall accumulations for this event were generally in the 30 to 40 millimetre range across south western and south central Ontario with the Hamilton area receiving the largest amount at 78.1 millimetres. Gusty winds from the northeast were also associated with this storm system. Wind gusts in some areas reached 60 kilometres-per-hour with the strongest wind gusts reported in the Hamilton area, reaching 78 kilometres per hour. These winds brought down tree branches and caused sporadic power outages.

Temperature and Precipitation Tables
Record mean temperature readings (in °C), ranked by variation from normal:
Location	Mean Temp	Normal	Difference	Previous Record
Chapleau	8.1	3.9	4.2	7.2 (2007)
Dryden	8.7	4.5	4.2	8.0 (1973)
Geraldton	7.0	3.1	3.9	6.5 (1994)
Unusual mean temperature readings (in °C), ranked by variation from normal:
Location	Mean Temp	Normal	Difference	Warmest since
Moosonee	7.7	3.4	4.3	1947
Sioux Lookout	8.3	4.2	4.1	1963
Kenora	9.0	5.1	3.9	1963
Pickle Lake	6.3	2.4	3.9	2006
Wawa	8.4	4.7	3.7	1973
Kapuskasing	7.2	3.8	3.4	1973
Earlton	8.2	4.9	3.3	1971
Red Lake	7.0	3.7	3.3	1973
Timmins	7.1	4.2	2.9	2007
North Bay	8.8	5.9	2.9	2007
Petawawa	9.1	6.3	2.8	2007
Sudbury	8.5	5.8	2.7	2007
Sault Ste Marie	9.6	7.0	2.6	2007
Thunder Bay	7.5	5.0	2.5	2007
Trenton	10.5	8.3	2.2	2007
Peterborough	9.5	7.3	2.2	2007
Ottawa	10.0	7.8	2.2	2007
Unusual rainfall readings (in mm), ranked by variation from normal:
Location	Rainfall	Normal	Difference	Least rain since
Geraldton	26.2	58.7	-32.5	2009
Location	Rainfall	Normal	Difference	Most rain since
Wiarton	167.0	86.9	80.1	1954
Toronto Pearson	119.2	63.4	55.8	2006
Hamilton	125.0	71.6	53.4	1995
Red Lake	78.0	35.9	42.1	2007
Windsor	102.4	64.1	38.3	2006
North Bay	126.2	92.2	34.0	2009
Connaught (near Timmins)	94.6	64.0	30.6	2005
Sudbury	107.0	76.8	30.2	2009
Sault Ste Marie	108.6	80.3	28.3	2009
Unusual precipitation readings (in mm), ranked by variation from normal:
Location	Precipitation	Normal	Difference	Driest since
Geraldton	29.2	80.6	-51.4	1992
Wawa	71.4	121.4	-50.0	2010
Kapuskasing	48.6	81.2	-32.6	2010
Moosonee	46.4	73.3	-26.9	2003
Location	Precipitation	Normal	Difference	Wettest since
Wiarton	167.0	91.0	76.0	2006
Kitchener-Waterloo	124.7	65.6	59.1	2001
Toronto Pearson	119.2	64.1	55.1	2006
Hamilton	125.0	72.5	52.5	1995
Toronto City	111.1	64.7	46.4	2001
Red Lake	94.8	52.4	42.4	1999
Windsor	102.4	64.9	37.5	2006
North Bay	126.2	97.6	28.6	2009
Sudbury	107.2	82.1	25.1	2009

Note: The normal period used is the 1971-2000 Climate Normals 

Media: For more information, please contact:

Laurie Thibeault
Communications Advisor
Environment Canada – Ontario
905-336-4711