Frigid low temperatures Friday morning brought Eau Claire's first freeze of the fall. Eau Claire dropped to 30 degrees, which was just a degree above the daily record coldest low of 29 set in 1929.
Medford had a hard freeze with a low of 26! In fact, almost all of Western Wisconsin froze, with the exception of some spots in the Mississippi River Valley.
This first freeze for Eau Claire was earlier than average, about halfway between the earliest on record and the average of September 30. In fact, September 18, 2020 ties for 13th earliest first freeze on record, which puts it around the top 10% of earliest first freezes.
With plenty of sunshine, that morning frost melted and afternoon temperatures rose to around 60, though that's still about 10 degrees below average. Expect another cold night into Saturday morning, but lows will be a bit warmer as the core of the coldest air has shifted east.
A Frost Advisory is in effect for Clark and Jackson counties, with Taylor and counties to the north no longer receiving any alerts as they've already received a hard freeze, effectivly ending the growing season and ending the need for frost or freeze alerts.
We will stay sunny through the weekend, though it will be a bit windy both days. The good news is the wind is bringing in warmer air, and by Sunday the highs will be in the low 70s. Monday will rise to the mid 70s as a warm front moves through with only a slight chance of light rain, and by Tuesday temperatures will be near 80 with some humidity again in the air.
The fact that Tuesday is the Autumnal Equinox just further proves that the weather pattern doesn't always follow the calendar. In fact, Septmber and October are the transition season, and while that means fall temperatures are more likely, in reality we see a lot of temperature swings this time of year as the polar jet stream gets closer to us and fuels the formation of fronts. Warmer weather is expected to last through at least the end of next week.