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Ontario Weather Review - December 2004
Call December 2004 a month of extremes in both temperatures and snowfall.
At the beginning of the month, temperatures were extremely mild. Then, they turned extremely cold. Finally, they ended on a very mild note. Overall, the frigid Arctic air prevailed and the mean monthly temperature for December was below normal across the entire province. While the majority of locales were 0.5 to 1 degree colder than normal, central and northeastern Ontario were 2 to 4 degrees below usual December readings, making December 2004 the coldest in this part of the province since at least 2000 and, in some cases, since 1989.
Snowfall was another extreme - as in extremely variable. While North Bay's 121 centimetres were double its normal total and the snowiest since records began there in 1939, Kapuskasing's meagre 22 centimetres was less than 50 per cent of normal and its lowest December snowfall total since 1937. In general, however, December 2004 was a snowier month than usual in most locations.
Ontario also endured a number of stormy days as mild moist air dueled with cold Arctic air. One significant result was a storm that raced through southern Ontario on December 23, accompanied by a wintry mix of heavy snow, ice pellets and freezing rain. Between 20 and 35 centimetres of snow fell northwest of a line from Long Point to Renfrew, while several hours of freezing rain and even rain fell in eastern Ontario, including Kingston, Cornwall and Ottawa. Treacherous roads, some local flooding and numerous cancellations ensued.
Unusual mean temperature readings:
| Location | Mean Temp. | Normal | Difference | Coldest since |
|---|
| Kapuskasing | -18.1 | -14.3 | -3.8 | 1989 |
| North Bay | -11.5 | -9.1 | -2.4 | 2000 |
| Sudbury | -11.7 | -9.5 | -2.2 | 2000 |
| Sault Ste Marie | -8.0 | -6.3 | -1.7 | 2000 |
Unusual snow readings (in cm):
| Location | Snow | Normal | Difference | Most since |
|---|
| North Bay | 121.0 | 61.3 | +59.7 | Records began in 1939 |
| Sault Ste Marie | 126.4 | 80.8 | +45.6 | 1995 |
| Red Lake | 69.0 | 31.6 | +37.4 | 1967 |
| Sarnia | 49.7 | 30.3 | +19.4 | 2000 |
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| Location | Snow | Normal | Difference | Least since |
|---|
| Kapuskasing | 22.4 | 57.4 | -35.0 | Records began in 1937 |
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