Week of 9/13 - a taste of fall for many of us
Posted: Sun Sep 13, 2026 3:56 pm
Much of Michigan will see its first taste of autumn like temperatures this coming week, although there will be some pleasant weather mixed in, too. Much of western and especially northern lower MI is getting a taste of autumn right now (mid-afternoon on Sunday, 9/13). Some isolated low temps in the upper 30s even cannot be ruled out across northern lower Michigan tonight!
Aside from this afternoon or evening, rain chances will exist from Tuesday afternoon into Thursday morning and again on Saturday.
9/19 looks like it could be an active severe weather day for portions of Illinois, Indiana and possibly Ohio.
My forecasted high temps for Detroit and for Grand Rapids:
9/13: 80, 72 (already reached)
9/14: 72, 69
9/15: 79, 74
9/16: 74, 70
9/17: 74, 74
9/18: 73, 73
9/19: 72, 67
9/20: 67, 65
GFS model run from 8AM this morning; first number is projected 5PM temp for Detroit and second number is projected 5PM temp for Grand Rapids:
9/13: 79, 57 (no, that isn't a typo. GFS is forecasting a cold rain at 5PM. It isn't completely absurd; it is rainy and 60 at Muskegon right now. Low or mid 60s are probably what it'll be in GR at 5PM.)
9/14: 72, 74
9/15: 77, 69. Very tight thermal gradient from the Great Lakes to the Ohio River; 90+ in central Indiana.
9/16: 77, 65
9/17: 74, 76
9/18: 75, 76
9/19: 77, 71 (strong warm front makes it to about I-80). GFS shows heavy rainfall across much of lower Michigan.
9/20: 64, 62 (front pushes south as a cold front)
Euro-AIFS (Artificial Intelligence Forecasting System) model run from 8AM this morning; first number is projected 2PM temp for Detroit and second number is projected 2PM temp for Grand Rapids (I was unable to obtain 5PM data from this source):
9/13: 79, 70
9/14: 67, 69
9/15: 77, 74
9/16: 71, 71
9/17: 71, 71
9/18: 70, 70
9/19: 67, 61 (this model hangs up the warm front about 100 miles farther south, keeping lower Michigan in very cool air)
9/20: 68, 64
Aside from this afternoon or evening, rain chances will exist from Tuesday afternoon into Thursday morning and again on Saturday.
9/19 looks like it could be an active severe weather day for portions of Illinois, Indiana and possibly Ohio.
My forecasted high temps for Detroit and for Grand Rapids:
9/13: 80, 72 (already reached)
9/14: 72, 69
9/15: 79, 74
9/16: 74, 70
9/17: 74, 74
9/18: 73, 73
9/19: 72, 67
9/20: 67, 65
GFS model run from 8AM this morning; first number is projected 5PM temp for Detroit and second number is projected 5PM temp for Grand Rapids:
9/13: 79, 57 (no, that isn't a typo. GFS is forecasting a cold rain at 5PM. It isn't completely absurd; it is rainy and 60 at Muskegon right now. Low or mid 60s are probably what it'll be in GR at 5PM.)
9/14: 72, 74
9/15: 77, 69. Very tight thermal gradient from the Great Lakes to the Ohio River; 90+ in central Indiana.
9/16: 77, 65
9/17: 74, 76
9/18: 75, 76
9/19: 77, 71 (strong warm front makes it to about I-80). GFS shows heavy rainfall across much of lower Michigan.
9/20: 64, 62 (front pushes south as a cold front)
Euro-AIFS (Artificial Intelligence Forecasting System) model run from 8AM this morning; first number is projected 2PM temp for Detroit and second number is projected 2PM temp for Grand Rapids (I was unable to obtain 5PM data from this source):
9/13: 79, 70
9/14: 67, 69
9/15: 77, 74
9/16: 71, 71
9/17: 71, 71
9/18: 70, 70
9/19: 67, 61 (this model hangs up the warm front about 100 miles farther south, keeping lower Michigan in very cool air)
9/20: 68, 64