If the 2015 Summer has seemed unusually pleasant, that’s because it has been!
Here we are at summer’s half-way point, and we have seen no major heat waves, no consistently unbearable humidity levels, and we have not had much in the way of widespread excessive rainfall. Indeed, we appear to be in the midst of a relatively comfortable, inoffensive summer.
So, how unusual is this predominantly tolerable summer weather, and is there a way to quantify and rank it?
The all-new Summer Glory Index (SGI) can help us answer these questions. Any day from June through August can earn up to 40 Glory points for being within “ideal” temperature, dew point, and precipitation ranges, and can lose points for being too hot, cold, wet, or humid. A given year’s SGI is then the sum of all the points earned and lost, and tells us how frequently we’ve experienced glorious conditions. Like its counterpart, the Winter Misery Index, the SGI allows us to compare individual summers to the historical record.
The index is based on measurements at MSP, which has a long digital record of dew point going back to the early 20th century.
Through July 15, this summer has been the third most glorious on record. Only 1922 and 2008 were better. Our current high ranking should come as no surprise: to date, Minneapolis has only topped 90 degrees once, has not recorded a minimum temperature of 70 or greater, has only had one 6 PM dew point reading above 70 degrees, and has had just two calendar days with over an inch of rain.
Of course, there is no guarantee that the second half of summer will match the first half’s splendor. Nine of the top-10 summers up through July 15th slipped to between 19th and 69th for the second half of the season, and the summer of 1940, after a stellar first half, had one most miserable second halves on record. Stay tuned to find out how this currently-spectacular summer finishes.
For more background, including how points and penalties are assigned, and to see a graph of annual totals, please see our Summer Glory Index page.
Update: Classical, summerlike conditions (warmer, more humid) during the second half of July caused our ranking to drop to as low as #8 on the all-time list. Extraordinary conditions have resumed in earnest, however, and the score through August 4th puts us back into 5th place.
Last modified: August 5, 2015