It was a record breaking mild weekend in Winnipeg as an unprecedented stretch of above freezing temperatures turned ice rinks and streets into puddles and slush across the city. The temperature at Winnipeg airport (where official temperatures are measured) rose above freezing at 4 am Friday morning Jan 20th, and stayed above freezing until 11 pm Sunday evening Jan 22nd. The stretch of 67 straight hours above freezing set a new record for the longest January thaw on record in Winnipeg, eclipsing the old mark of 44 straight hours Jan 8-9th 2002.
Hourly temperature records for Winnipeg airport go back to 1953, but even looking at daily records shows that the 67 hour thaw is likely the longest such stretch in January in Winnipeg since records began in 1873. The only other comparable January thaw* would have been Jan 9 - 12 1928 when the temperature failed to drop below -1.6C over the 4 day period. However even then, there wasn't a 48 hour period where the temperature was consistently above 0C, so it appears this most recent warm spell is the longest such streak for January in Winnipeg in 144 years of weather records. (*NOTE: "January thaw" in this case is defined by consecutive hourly temperatures of 0.0C or more. There have been longer stretches in January where daily high temperatures have reached 0.0C or higher, but temperatures dropped below freezing at night. The longest stretch with daily highs of 0.0C or more in Winnipeg in January was 9 straight days in January 1942 from the 16-24th, with 14 in total during the month, including Winnipeg's all time January high of +7.8C on the 23rd)
The 3 day thaw also set new daily record high minimum temperatures in Winnipeg from Jan 20 to 22nd inclusive:
|Record daily minimum temperatures set Jan 20-22 2017 |
(table courtesy of @jjcwpg)
Normal lows for this time of year are near -23C, so these temperatures are almost 25C above normal lows! The low of +0.9C on Jan 21st was only the third time in 144 years where the temperature did not drop below freezing during a January day in Winnipeg. The only other dates were Jan 12 1928 (minimum of +1.1C), and Jan 14 1894 (minimum of 0.0C). Thus, a 67 hour streak of above freezing temperatures in January in Winnipeg is an exceedingly rare occurrence. Note also that 2.9 mm of rain fell on Jan 20th, the 2nd highest rainfall for any January day or month since 1873 (second only to the 3.8 mm that fell on Jan 20 1944) The mild weather, although welcome after a frigid first half of January, forced the closure of city rinks and skating trails as ice melted into slush and giant puddles. The thaw also resulted in locally slippery streets and walkways as water slicked up packed snow and ice.
Temperatures are slowly cooling off this week to below freezing, but will remain above normal values the rest of the week before more seasonable temperatures return by the weekend.