#4, #3 and #2 - Top 10 Weather Stories of 2013 in The Winnipeg Area

(The order of the top 3 weather stories of the year has been determined by the results in the top weather stories poll! Thanks to all of you who participated!)

#4 - Summer heat; better late than never!

     After a rather cool mid-summer, hot and humid conditions returned by mid August, salvaging summer.

     A prolonged period of well above normal temperatures began mid August. In fact, in the last 16 days of the month, highs averaged 30.0°C and lows 15.5°C, both about 5°C above normal for the period. 10 days reached 30°C, above the normal of 5 for August and the most 30°C days in August since 2003. It was also humid with an average daily maximum humidex of 34.6 (in the last 16 days of the month). 8 days saw humidex above 35, well above the 1971-2000 normal of 3 for August. The maximum was 40.4 August 24.

     The peak of the heat occurred during a 4-day heat wave Aug 25-28 when highs reached 33-34°C. This was the longest heat wave since July 2011 (4 days long) and the longest in August since 2003 (7 days long). We hit 30°C for 5 consecutive days, the longest streak in August since 2003. Two high minimum records were broken, a 21.4°C low Aug 24 and a 19.7°C low Aug 25.

     The warmth continued in September, offering an extended summer. With an average mean of 15.4°C, we tied with 1920 for 8th warmest September since 1872.

Sep 6 t-storms after a super-hot day southeast of Wpg

     September 6 featured one of the hottest September days in history. A high of 33.8°C was the hottest in September in 30 years since a high of 38.8°C Sep 2, 1983. Although this was not a record daily high, a low of 17.9°C that day broke a high minimum record. Humidity was also unusually high. A maximum dewpoint observation of 20.3°C was the highest in September since Sep 5, 2005. Humidex peaked at 40.4, only the 4th occurence of humidex over 40 in September since 1953. This was also the latest occurence of humidex over 40 on record.

     The period was also quite dry. From August 19 to September 25 (38 days), just 7.0 mm of rain fell. This was quite reminiscent of last year's 2nd driest September on record.

#3 - The "Perimeter shields" in full action

     The Winnipeg thunderstorm deadzone, Perimeter shield or however else you want to call it, continued into 2013. The year proved to be one of the worst years on record for thunderstorms in Winnipeg. With just a measly 17 thunderstorm days at the airport, this tied for 4th least in a year since 1953.

     The season had a very rough start due to an extremely delayed spring. For the first time since 1995, Winnipeg did not record a single thunderstorm in May. In addition, this was only the 9th occurrence since 1953. Winnipeg finally recorded its first storm on June 10, making it the second latest start to the thunderstorm season (normal first t-storm is April 26). Even more striking, this ended a 289-day streak without a thunderstorm, the longest period without a thunderstorm on record:

Top 5 longest periods without thunderstorms in Winnipeg since 1953
Rank	Length	Period
1	289 days	Aug 25, 2012 to Jun 10, 2013
2	286 days	Sep 14, 1957 to Jun 28, 1958
3	271 days	Aug 16, 1967 to May 14, 1968
4	264 days	Aug 26, 2006 to May 18, 2007
5	261 days	Sep 10, 2010 to May 30, 2011

     The thunderstorm deprivation continued into part of the summer. Only 2 thunderstorm days occurred in August, tying with 1970 and 1971 for 2nd least on record for August. With 3 thunderstorm days in September, this was only the 4th time since 1953 that there were more thunderstorm days in September than in August.

     And finally, the thunderstorm season only lasted 124 days this year at Winnipeg airport (June 10 to October 11), the 8th shortest season on record.

#2 - Bone-chilling December a fitting end to a "cold" year

     It was the type of December where you only went outdoors if you absolutely had to. With an average mean temperature of -20.9°C, December 2013 was the 6th coldest on record since 1872. It was the coldest December since 2000 and the 2nd coldest since 1893. In total, 9 days dipped below -30°C, above the normal of 3. In addition, 14 days never rose above -20°C, something that is unusual even for January standards. Wind chills were another story, with an average daily minimum wind chill of -35.4. In fact, 12 days saw wind chills below -40, triple the normal of 4 days. A wind chill of -48.0 on December 31 was close to the all-time December low of -50.6 on December 20, 1989. At one point on December 30, the entire province was under a wind chill warning.

     A morning low temperature of -37.3°C on December 15 not only broke a daily record low, but was also the coldest temperature for so early in the season since a low of -39.4°C on December 10, 1893. In addition, a low of -37.9°C on December 31 was the coldest temperature in December since 1933.

     The extreme cold help push some impressive milestones. According to CBC Manitoba, CAA Manitoba reported that December 2013 was its busiest month on record. In addition, Manitoba Hydro reported a record in electricity use across the province on December 23. The cold also delayed trash and recycling collection in Winnipeg.

     Thanks partly to a December that was over 7 degrees below normal, 2013 ties as the 33rd coldest year since 1873. However, it was the coldest year since 1996 and tied 11th coldest in the last century.