Minnesota Experiences 66 Degree Temperature Range at One Time

Minnesota is a fairly large state and can experience a wide range of temperatures. Occasionally, there can be a 40 degree range of temperature across the state at any given time and on rare occasions, a 60 degree range. On Tuesday, May 19, Minnesota experienced a temperature range of 66 degrees. At 5:00 PM (CDT) the temperature in Granite Falls, in southwestern Minnesota reached 100°F. At the same time, Grand Marais, in the northeastern part on the state, recorded a temperature of 34°F, due to the lake breeze off of Lake Superior. (The high in Grand Marais only reached 42°) The hot temperatures by themselves were record setting. Minneapolis/St. Paul reached 97°F, setting the record for the warmest temperature so early in the season. Previously, the earliest date to record temperature of 97° was May 22, back in 1925, and only three years have ever had a 97°F reading in May prior to yesterday: 1925, 1934 and 2006. While the warmest reading for the month of May occurred in 1934, at 106°F, only about half the years between 1890 and 2006 have recorded 97°F or hotter for the entire year.

Minnesota Temperatures - 5/19/09 5:00 PM CDT - Click for Larger

In the above image, you can see the range of temperatures across the state. On each weather icon, the temperate (°F) can be seen as the number to the upper left of the circle in the center of the icon. The circle itself indicates the percentage of cloud cover. You can also see the wind direction. The little wind vane sticking out of the circle shows the direction from which the wind is blowing. You can clearly see the areas that are coldest are experiencing winds from the east or southeast. These easterly winds are cooler as they are blowing across the cold Great Lakes. However, in areas where temperatures soared to the upper 90s to 100°F, you can see the predominant wind direction is from the south and southwest. Here, the air is not influenced by any body of water, but rather by the warm, dry air from the Plains States. Also at work was a phenomenon called compressional, or adiabatic heating, where the air is warmed as it sinks and is compressed by high pressure.

Not only were these temperatures and the range of temperatures across the state interesting, it was rather rare for Minnesota to experience some of the hottest and coldest temperatures in the lower 48: At the time it was 100°F in Granite Falls, it was 21 degrees colder in Houston, TX, at 79°F and 25 degrees colder in Miami, FL, at 75°F.

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