April may have started warm and ended cool, but the for the 20th month in a row in the Twin Cities (and some other locations), the above-normal temperatures prevailed.
March 2017 was a close call, barely finishing warm, but April's warmth was somewhat more convincing, though not in the same manner as February (as just one example). Twenty of the first 25 days of the month were warmer than average in many locations, and the five days that were not instead were only slightly cooler than average. Temperatures plummeted behind a cold front towards the end of the month, which ended on a markedly chilly note, but the cold air was too little, too late. Every airport with long-term records finished warmer than 1981-2010 normals, generally by 2-3 degrees F.
In the Twin Cities, the average monthly temperature has now been above the 1981-2010 normal for 20 months in a row, meaning that MSP airport has not recorded average below-normal monthly temperatures since August 2015. This is also true for St. Cloud. For both stations, this is the longest above-average monthly temperature streak of any kind on record, though it is worth noting that the "normals" refresh every 10 years, and procedures for calculating them have changed over time. As of this writing, only five months out of the last 35 (back to June 2014) have been below normal in the Twin Cities. The second longest streak on record was 16 months, from June 2011 through September 2012.
This climatological decade (beginning January 2011), over 70% of months have been above the 1981-2010 normals. In the previous climatological decade, 68% of months were above the 1971-2000 normals, and the Twin Cities has not had a string of 10 or more cool months since 1964-65. Indeed, the whole of Minnesota has been warming rapidly since about 1970, making above-normal temperatures more likely than below-normal ones, even as the baseline values are updated to reflect the warmer conditions.
Twin Cities Average Monthly Temperatures
Avg Dept. from Month Year Temp 1981-2010 Normal --------------------------------------------- September 2015 67.9 + 5.9 October 2015 52.1 + 3.2 November 2015 41.3 + 7.6 December 2015 30.2 +10.5 January 2016 17.6 + 2.0 February 2016 24.9 + 4.0 March 2016 41.3 + 8.5 April 2016 48.1 + 0.6 May 2016 61.3 + 2.2 June 2016 71.3 + 2.4 July 2016 75.2 + 1.4 August 2016 73.4 + 2.2 September 2016 66.1 + 4.1 October 2016 52.9 + 4.0 November 2016 44.1 +10.4 December 2016 20.9 + 1.2 January 2017 20.9 + 5.3 February 2017 31.2 +10.3 March 2017 34.0 + 1.2 April 2017 50.5 + 3.0