May and Spring 2018 Saint Cloud Weather Summary

May Reverses the Curse of Chilly April

May and Spring 2018 Saint Cloud Weather Summaries

After St. Cloud tied for the coldest April on record, the weather pattern quickly reversed. Heat built frequently over the Rockies and Plains and built into Minnesota. The net result was a May with 24 of 31 days warmer than average (after 28 of 30 April days being colder than average). The May 2018 average temperature ended up at 63.1 degrees, 6.5 degrees above average. This placed May 2018 as St. Cloud's 6th warmest May on record. The bulk of the heat was concentrated during a record 6-day heat wave (definition of heat wave is at least three straight days with a 90-degree high) from May 24 through May 29. There has never been a longer heat wave during May in St. Cloud records (longest only in May was May 27-29, 2006. There was a 6-day heat wave partly in May in 1934 (May 28 through June 4). It was St. Cloud's longest heat wave since July 23-31, 2016.

The 6 days with a high of at least 90 degrees were the most May 90-degree days in St. Cloud records. The old record was 5 90-degree days, set in May 1900 and May 1934. The 6 90-degree days are more than half the average total of 11.4 days and nearly half of the total of the past 4 summers combined (13 days).

During the heat wave, St. Cloud reached high temperatures of 95 degrees on May 26 ( broke a daily record) and 96 degrees on May 28. The 95-degree high was the first high of 95 degrees since August 26, 2013. The 96-degree high was the hottest St. Cloud temperature since June 7, 2011 (101 degrees). In fact, there have only been 2 days with a temperature of 96 degrees or higher since 2006.

Eventually, the warm weather brought up enough humidity to finally produce a decent amount of rain. Thunderstorms that ended the heat wave produced 1.34 inches between May 28 and 30. That's after going through a very dry period between the last accumulating snow on April 15 and these thunderstorms. During the April 16 through May 27 period, the St. Cloud Airport received only 0.59 inch. The average rainfall during the 6 week period is 3.97 inches. Between April 1 and May 29, most of central Minnesota has had less than half of the average rainfall, according to the weekly precipitation map from the Minnesota Department of Natural Resources with less than 10 percent of the average rainfall in western Stearns County and most of Morrison County. Portions of central Minnesota have seen less than 2 inches of rain in the past 30 days. Parts of northern Wisconsin and northern and central Minnesota are showing up as being unusually dry on this week's National Drought Monitor from the National Drought Mitigation Center. Still, most near surface and sub-surface moisture in the last USDA Weekly Minnesota Crop Progress and Condition report from May 29 (index of all reports found here) is average.

The end of May completes the meteorological spring (March 1-May 31), since June, July and August make up meteorological summer (three warmest months of the year). The extremely warm May was on the heels of the record cold tying April 2018, so the average St. Cloud temperature for March 1-May 31 was 41.7 degrees, 1.8 degrees colder than average. The 5.15 inches of precipitation was 1.92 inches less than average. The leftover from the cold season still produced the 6th snowiest spring in St. Cloud records with a total of 30.2 inches. Note that 4 of the 7 snowiest springs have occurred since 2002. The persistent snow and cold led to lake ice out dates between 3 and 4 weeks later than average.