Is This "Indian Summer"?
The answer to that question is yes and no. It is Indian Summer for parts of northern Illinois but for most of us it isn't.
Monday morning was the coldest of the season so far but not cold enough for the warm up that has followed to fit the criteria of an official Indian Summer.
Here is the definition of an Indian Summer according to the National Weather Service:
True Indian Summer is a period of abnormally warm weather following the killing freeze of autumn. A killing freeze occurs when the overnight temperature reaches 28 degrees or colder and may or may not occur with frost.
Aurora was the only area that fell to 28° on Monday so it is the only spot locally that could officially be enjoying Indian Summer weather.
The median date for the first fall freeze in northern Illinois is any time between the middle of October to early November depending on the exact location. It arrives latest in the city and earliest in the northwest corner of the state.
Sensational Stretch Of Weather
Whatever you want to call this stretch of sensational weather, it is beautiful. After the first five days of October coming in below average, yesterday bounced back above average with a high of 75°. Average highs for early October are around 66°. Today's highs will also be above average with most of us topping out in the lower to middle 70s.
Above average temperatures keep on coming all the wary through the weekend into early next week. Most days will be into the 70s with highs approaching 80° on Friday. Tuesday will be the coolest of the next seven days with highs in the lower to middle 60s.
Most of the longer range forecasts keep us above average. The 6-10 day temperature probability forecast has us outlooked for above average temperatures overall from October 12th through the 16th. The 8-14 day forecast has us near normal from the 14th through the 20th.
The multi-model ensemble temperature anomaly forecast has the midwest outlooked (and most of the country) for above average temperatures the week ending October 23rd. This mild pattern could help us overcome the cool start to this month allowing October to finish above average overall for the month like every other month this year except April.
Dry Through The Weekend
A mostly dry pattern should continue through the weekend. There is only a slight chance for a spotty shower late Saturday into early Sunday. The next decent chance for rain is late Monday into Tuesday. There is some model disagreement about that threat of rain though so confidence in getting some showers is not high at this point.
The 6-10 day precipitation probability forecast has us outlooked for above average rainfall from October 12th through the 16th. The 8-14 day forecast has us returning to near normal precipitation from October 14th through the 20th.
Here is my 7 day forecast:
Today: Mostly sunny, breezy High: 73
Thursday: Sunny skies Low: 49 High: 70
Friday: Mostly sunny, breezy Low: 52 High: 79
Saturday: Partly to mostly sunny Low: 59 High: 72
Sunday: Mostly sunny Low: 53 High: 68
Monday: Partly cloudy, shower possible late Low: 54 High: 71
Tuesday: Partly to mostly sunny Low: 53 High: 65