We had quite a heat wave to open the month. However now, the hot weather is only a memory. Through yesterday, there’s been over a week of below average temperatures.

In recent times, temperatures of 90 or above in September have been confined to the first 10 days or so of the month. For instance, the National Weather Service’s latest 90-degree high was on September 11, 1998. On the other hand, Houghton’s latest 90 was on the 15th in 1939, while it hit 90 in Munising on the 18th in 1955. Residents in Iron Mountain perspired because of a 90-degree temperature as late as the 22nd in 1908, and in Marquette, the latest 90 is over a week later on the last day of the month–September 30!

Remember, the greatest U.S. summer heat waves occurred during the 1930s. In the U.P., the greatest, latest September heat waves were also in the 1930s. Marquette and Munising both had three consecutive days with highs in the 90s September 10-12, 1931, while Iron Mountain and Ironwood racked up four straight days in the 90s. Then, eight years later, Ironwood had three straight 90s from the 13th through 15th in 1939.

Here’s more proof that it was hotter in days gone by. Records at the National Weather Service only go back to 1961. There, only six calendar days in September have record highs in the 90s. Houghton, where records go back to the turn of the 20th century has 10 calendar days, Munising 16 days, Iron Mountain 18 days and Marquette, where records go back to the Civil War, has 24 calendar days in September with highs in the 90s!

While 90-degree temperatures are unlikely, some warm days are still ahead. We’ll start out with near to below average temperatures this weekend with readings warming into the 70s next week.