Saturday, 1 March 2014

A Truly ''Old Fashioned'' Winter

     A worst winter nightmare come true? Not only was this winter the 11th coldest but it was also the 11th snowiest (since 1872). Due to this combination, along with frequently strong winds, it really was about as harsh as winters get around here.

     With 101.6 cm of snow in Winnipeg from December to February, it was also the snowiest winter in 52 years (116.5 cm in the winter of 1961-62). With an average mean temperature of -20.3°C, it was also the coldest winter in 35 years (-20.8°C in the winter of 1978-79). It was also the 3rd coldest in 120 years!

     Of course, it was the persistence of the cold rather than its intensity that was the story this winter. All three winter months averaged -20.0°C or colder, only the second time that this has occurred since 1872 (last time was the winter 1886-87).

     Perhaps the following is the most amazing statistic. 75 days this winter dipped below -20°C, the 4th most -20°C days in a winter since 1872. That's 83% of all the winter days! The following table shows the top 5:

Table: Top 5 most -20°C days in a winter (Dec-Jan-Feb) since 1872

# of days ≤ -20.0°C
80 days
79 days
77 days
75 days
73 days

     And the following table briefly summarizes temperatures this winter:

Winter 2013-14
Rank (since 1872)
Most/least since…
1981-2010 normal
Days below -30°C
27 days
23rd most (tied)
1995/96 (28 days)
13 days
Days below -20°C
75 days
4th most
1886/87 (77 days)
46 days
Days above -10°C
24 days
8th least (tied)
1977/78 (17 days)
50 days

      Blame the harsh winter on the jet stream... which has been more or less locked in a persistent pattern for the past 3 months and unfortunately, we have been under the troughing part of the jet stream for most of the winter.

     Now, let's list the extremes seen this winter...
  • A low 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 1893 (-39.4°C on Dec 10, 1893).
  • A low of -37.9°C on December 31 was the coldest in December since 1933 (-41.1°C on Dec 28, 1933)
  • December was the 6th coldest on record (average mean of -20.9°C)
  • A daytime high of -30.2°C on January 5 not only broke a daily low maximum record, but was also the first daytime high below -30°C since 2004 (-30.8°C on Jan 30, 2004).
  • 6 days dipped below -35°C, lowest reading being -38.0°C on January 5.
     And finally, the one storm system to emphasize this winter was on January 15. Not only were record highs broken (high of 3.3°C in Winnipeg), but thundersnow reportedly occurred west of Winnipeg associated with a strong cold front in the evening (according to Brad from A Weather Moment). However, the high of 3.3°C in Winnipeg was an incredible 30.7°C rise from a low of -27.4°C the same morning. This makes it the greatest single-day warmup on record since 1872 (''single-day'' being equivalent to ''calendar day''). The following table shows the top 5 greatest single-day warmups:

Table: Top 5 greatest single-day (''calendar day'') warmups since 1872

Magnitude of warmup
Jan 20, 1874
May 12, 1949
May 19, 1899
Jan 30, 1934

     Note that this statistic does not consider how quickly the warmup occurred. On January 15, the 30.7°C warmup occurred in about 14 hours, which is one of the fastest warmups on record. However, in the past even more rapid warmups have occurred. An example was on April 28, 1985 when the temperature rose 26°C in just 8 hours (from 4°C to 30°C).

     Thanks for reading and here's hoping for some warmer weather! (Although we have to admit, a slow warmup is preferable this spring due to the amount of snow cover).

*A temperature difference of  31.1°C on January 25, 1889 was not included because it appears it may have been a cool down and not a warmup (can't say for sure because there's no hourly data).


  1. The weather poll worked well for this morning's low (the most popular vote was correct)! Congrats to the 5 repondents who answered -35.0°C to -37.7°C! Official low was -37.0°C at Winnipeg airport.

  2. Excellent summary Julien. Didn't realize the # of -20C days was so high compared to the late 1800 winters.. that's a pretty telling statistic! Really emphasizes the prolonged cold this year as opposed to the intensity.

    1. Thanks Rob..
      I was surprised by that statistic as well.. I never expected we would challenge the extreme winters of the late 1800's again! Quite the winter.

  3. Looks like an all-time March low maximum will not be broken today; high of -26.2°C as of 5 pm. But we'll easily break the old low maximum of -22.2°C for today.

  4. Re: Single calendar day warmups.

    Interesting list. Personally, I find the 34.4C jump on Mar 19 1887 hard to believe (low of -31.1C, high of +3.3C). The day before had a maximum of -2C and the next day was 0C. Hard to imagine that the temperature would drop to -31C during such a stretch. Note that -31.1C is -24F. Back then they used F, so it's quite possible the low on March 19th should have been +24F (-4.4C), not -24F. Note that climate obs from nearby Stony Mountain had a high of +2.2C and a low of -6.1C on March 19th, which seems more reasonable.

    If that's the case, then the 30.6C warmup this January 15 could be the greatest calendar day temperature rise on record for the city.

    1. Wow, didn't realise Stony Mountain had a weather station back then! You make a really good point Rob... and that Stony Mountain observation I think is confirmation enough that that -31.1°C reading for Winnipeg is likely erroneous.
      Thanks for pointing that out!

    2. I think you've given enough evidence to support the rejection of that -31.1°C... Therefore, I'm now considering the 30.7°C warmup on January 15 as the greatest single day warmup. New top 5 updated in this post accordingly.

    3. Also turns out that -31.1°C was considered a record low for March 19... will have to get rid of that from the record!

  5. Do any of the old weather stations nearby go back to 1840

    1. JJ C This might be of interest. Came across a commentary on Data Collection and the Brutal winter of 1886-7 at the Univ of Minn. It includes comments on the Pembina weather station reading of -62. Like this group of cold winters it was preceded by an equally warm one. Don