Three summers in Minnesota? Astronomical summer at 5:07 a.m. Thursday

The summer solstice arrives as the sun is poking up Thursday morning. It's the longest daylight of the year in Minnesota.

Three summers?

You might say we get three summers in Minnesota.

• "Unofficial summer" begins Memorial Day weekend and lasts through Labor Day.

• Meteorological summer began on June 1 and ends Aug. 31.

• Astronomical summer begins June 21 and runs until Sept. 22.

Maybe we deserve three summers in Minnesota?

Here's a good description of the differences between meteorological and astronomical seasons.

You may have noticed that meteorologists and climatologists define seasons differently from “regular” or astronomical spring, summer, fall, and winter. So, why do meteorological and astronomical seasons begin and end at different times?

In short, it’s because the astronomical seasons are based on the position of Earth in relation to the sun, whereas the meteorological seasons are based on the annual temperature cycle.

Sun furthest north 

Thursday marks the point in the Earth's orbit when the sun is highest in the sky in the northern hemisphere.

Gradually warmer temperatures

Temperatures rise slowly the next week or so. There are signs we may touch the 90-degree mark again by the first week of July.

Showers south

Low pressure spinning in Iowa will keep a few pesky showers and thunderstorms in southern Minnesota through Thursday. Rain chances for the Twin Cities are low, but I can't rule out a brief pop-up shower Thursday afternoon.

Here's the National Oceanic and Atmospheric Administration's North American Mesoscale Forecast System 3 km resolution model through Thursday.

Lake Superior bathtub ring

All that outwash from floods around Lake Superior this week is visible from space.