'Glory Index' ranks 2015 as 3rd best Minnesota summer on record

Chances are this last summer was one of the top two in your lifetime, weather-wise.

That's according to the State Climatology Office, a division of the Minnesota Department of Natural Resources. The agency developed a "Summer Glory Index" to measure the relative comfort of Minnesota summers — at least in the Twin Cities, since that's where records go back the furthest for historical calculations.

The summer of 2015 ranked third in the climate record, behind 1922 and 2008, according to senior climatologist Kenny Blumenfeld, who is the originator of the index.

It's a flip side of the "Winter Misery Index" that gauges Minnesota's more renowned season in December, January and February. The office updated its final rankings Tuesday, using data that run through June, July and August — the traditional meteorological summer.

June was already in the books as the best June weather in Minnesota weather history.

The summer stumbled toward the end with a steamy mid-August that threatened to knock 2015 out of the Top 10 rankings for records dating back more than a century. But it took a turn for the better as it closed.

Blumenfeld says he's been hearing from Minnesotans that it isn't just a good summer on paper. They've felt it.

"It is really the lack of humidity," Blumenfeld said of this summer's relative comfort. "For the majority of the summer, we really didn't have too many hours where the dew point temperature was about 70 degrees, and we certainly didn't have any long runs of time with really high dew point temperatures."

The temperature itself also stayed relatively low this year.

"I think we only went about 90 four times all summer, and that's much lower than the average," Blumenfeld said.

While some regions, including the Brainerd Lakes area, got hit with storms this summer, Minnesota stayed relatively free of heavy rainfalls, flooding or widespread wind or tornado damage.

Despite the relative comfort in Minnesota, this summer doesn't necessarily reflect a larger trend: climate change.

"It's very easy for us to confuse local with global," Blumenfeld said. "What we're seeing here is not representative of what's going on in other parts of the country or other parts of the world. The dominant trend is for places to get warmer most of the time. ... We're maybe getting some nicer summers right now. But I wouldn't take that to fly in the face of the science."

The index works like this: A day can earn up to 40 points.

• Ten of those points are for the high temperature, with a maximum awarded for peak temperatures between 73 and 79 degrees. Partial credit is awarded for higher and lower temps, and nothing for a day with a high lower than 67 or a high over 86.

• Ten points are awarded for a low between 57 and 64. Again, partial credit for lows near that range, and no credit for lows below 51 or over 67 degrees.

• Ten points are awarded for the 6 p.m. dewpoint, with maximum credit for values below 60 degrees.

• Ten points are awarded for rain fall less than 1/100 of an inch

"Penalties" can also be assessed for a variety of other conditions, such as high temperatures over 90, lows above 70 and more than an inch of rain.

A full explanation of the index is available online.