Frost Dates: First and last frost dates for Milwaukee Mt Mary Clg, WI
The charts on this page show the probabilities of receiving a certain temperature on a certain day. Some examples that might help:
- You have a small 20% chance of getting 32° by October 5.
- There is a 50% chance of being hit by a 32° frost starting around October 14
- You have a 80% chance of seeing 32° by October 24
- Said another way, you have a 1 in 5 chance at making it to that day without a 32° night.
Temperature | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
---|---|---|---|---|---|---|---|---|---|
First 16° | Nov 10 | Nov 16 | Nov 20 | Nov 23 | Nov 27 | Nov 30 | Dec 4 | Dec 8 | Dec 13 |
First 20° | Nov 5 | Nov 10 | Nov 13 | Nov 16 | Nov 19 | Nov 22 | Nov 25 | Nov 29 | Dec 4 |
First 24° | Oct 26 | Oct 30 | Nov 2 | Nov 5 | Nov 8 | Nov 10 | Nov 13 | Nov 16 | Nov 21 |
First 28° | Oct 15 | Oct 20 | Oct 24 | Oct 27 | Oct 30 | Nov 2 | Nov 5 | Nov 9 | Nov 14 |
First 32° | Sep 30 | Oct 5 | Oct 8 | Oct 11 | Oct 14 | Oct 17 | Oct 20 | Oct 24 | Oct 29 |
First 36° | Sep 24 | Sep 28 | Sep 30 | Oct 2 | Oct 4 | Oct 6 | Oct 8 | Oct 10 | Oct 14 |
What's a safe temperature for tender plants? When the nightly temperature falls, frost can form, even above 32°, because the air is colder high above the ground and the frost can form up there and then fall down onto your garden and do some damage, even if it's 36° on the ground. So many factors come into play, including wind, concrete, houses, trees and other structures, etc etc etc. Because of all this, you might want to consider 36° as "the danger zone".
In your average springtime, you have a 90% chance that there will be no 36° nights by May 24. In other words, you can pretty much count on being safe from frost by that day. But we want to get those tomatoes in the ground as soon as possible, right? We see that there's still an 80% chance of 36° on April 30, so we don't dare plant that early. We wait a few days and by May 9 we are at the 50/50 point. At this point, we are close and we can start watching the weather forecast. If the upcoming week's forecast doesn't show below 40°, then it's probably okay to risk planting out your plants.
Temperature | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
---|---|---|---|---|---|---|---|---|---|
Last 16° | Mar 31 | Mar 25 | Mar 21 | Mar 17 | Mar 13 | Mar 10 | Mar 6 | Mar 2 | Feb 23 |
Last 20° | Apr 8 | Apr 3 | Mar 30 | Mar 28 | Mar 25 | Mar 22 | Mar 19 | Mar 15 | Mar 11 |
Last 24° | Apr 15 | Apr 11 | Apr 8 | Apr 6 | Apr 4 | Apr 2 | Mar 30 | Mar 28 | Mar 24 |
Last 28° | Apr 25 | Apr 21 | Apr 18 | Apr 15 | Apr 13 | Apr 10 | Apr 8 | Apr 5 | Apr 1 |
Last 32° | May 10 | May 5 | May 2 | Apr 29 | Apr 27 | Apr 24 | Apr 21 | Apr 18 | Apr 13 |
Last 36° | May 24 | May 19 | May 15 | May 12 | May 9 | May 6 | May 3 | Apr 30 | Apr 25 |
Data is provided by the NOAA National Centers for Environmental Information.