Sunshine and warm temperatures capped a fitting end to March 2012 as temperatures once again soared well into the upper teens Saturday. In Winnipeg the high of 18.8C Saturday was just 0.1C off the record high of 18.9C for the 31st, set back in 1963. The balmy finish however propelled the monthly mean temperature in Winnipeg to +2.2C, easily the warmest March on record in the city since records began in 1872. The month was a whopping 8.3C above normal (30 year normal = -6.1C) and 0.6C above the previous warmest March of +1.6C set back over 130 years ago in 1878.
Top 5 warmest Marches in Winnipeg (since 1872)
1. 2012 .......... +2.2C
2. 1878 .......... +1.6C
3. 1910 .......... +1.0C
4. 1973 .......... +0.5C
5. 2000 .......... -0.1C
Normal .......... -6.1C (1971-2000 normal)
A historic 12 day March heat wave through mid month was responsible for the record breaking month, which helped set all time March records throughout southern Manitoba and a wide swath of central North America into the Great Lakes. The heat wave obliterated Winnipeg's 25 cm snowpack in just a few days between the 10th and 14th, with temperatures more typical of early May between the 11th and 23rd. The month set 8 new daily record highs in Winnipeg, including all time warmest March temperature of 23.7C on the 19th. The warm spell also helped kick start the growing season by a full 3-4 weeks.. a concern for plant growers worried about a return to more typical freezing temperatures in April and May.
A look at past history shows that their concerns are indeed warranted as a warm March does not necessarily translate into a warm spring. In fact, of the past 9 previous warmest Marches in Winnipeg, only 4 were followed by above normal temperatures in April, and ALL had below normal temperatures in May! Those springs had an average of 20 freeze days in April, and 9 in May with frosts well into mid to late May (even the first week of June some years!). And if history is our guide, don't put away the snow shovels just yet. Of those past 9 warm Marches, all were followed by some measurable snow in April (including a 25 cm snowstorm April 15-17, 1910), and 4 had snow in May. So don't let the warm start to spring fool you.. this is southern Manitoba after all, and a warm March is no guarantee that cold weather is over.