(FOX 9) - Some isolated spots in northeastern Minnesota have touched the freeze mark already this fall, everyone else has not. The coolest morning so far in the Twin Cities has had lows in the low to mid 40s and it may be at least another week before even cooling off that much, let alone getting to the low 30s.
If you look back over the last 30 years, the average first fall freeze in a sliver of northeastern Minnesota is actually before Sept. 15. It was these areas that reached the freeze mark last week, which technically was almost a week behind average. Now the rest of northern Minnesota generally sees the first freeze in the latter half of September, which even includes the extreme northern metro. The rest of the state, generally along and south of I-94, gets the first freeze in the early part of October.
For the Twin Cities though, it's more complicated. Because of the urban heat island effect, the suburbs typically get that first freeze before the metro core. Some years that can happen all on the same day. But in other years, the outer ‘burbs can get the first freeze three or four weeks before the metro core. For areas inside the I-494/I-694 loop, the typical first freeze is Oct. 13. For the ’burbs though, it's about a week earlier on the 7th.
We talk about the AVERAGE first freeze, but they can vary WILDLY from year to year. Over the last 30 years, the first fall freeze in the Twin Cities has ranged anywhere from Sept. 20 all the way to Nov. 18. That's why predicting such an event more than a few days in advance is tricky. Will that first freeze hold off a while?
Quite likely, yes. All signs point to an above average first half of October as a persistent ridge sits in the central United States. Notice the loop above showing plenty of varying degrees of red in the Upper Midwest over the next 10 days. That would likely spell plenty of 70s area wide over the next week or two with overnight lows staying well above the freeze mark.
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