Frost Dates: First and last frost dates for Willmar Wwtp, MN
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 September 23.
- There is a 50% chance of being hit by a 32° frost starting around October 1
- You have a 80% chance of seeing 32° by October 9
- 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° | Oct 28 | Nov 2 | Nov 5 | Nov 8 | Nov 11 | Nov 13 | Nov 16 | Nov 19 | Nov 24 |
First 20° | Oct 13 | Oct 19 | Oct 23 | Oct 27 | Oct 31 | Nov 3 | Nov 7 | Nov 11 | Nov 17 |
First 24° | Oct 8 | Oct 13 | Oct 16 | Oct 20 | Oct 22 | Oct 25 | Oct 29 | Nov 1 | Nov 6 |
First 28° | Sep 23 | Sep 28 | Oct 2 | Oct 6 | Oct 9 | Oct 12 | Oct 16 | Oct 20 | Oct 26 |
First 32° | Sep 19 | Sep 23 | Sep 26 | Sep 29 | Oct 1 | Oct 4 | Oct 6 | Oct 9 | Oct 14 |
First 36° | Sep 12 | Sep 15 | Sep 18 | Sep 20 | Sep 21 | Sep 23 | Sep 25 | Sep 28 | Oct 1 |
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 May 3, so we don't dare plant that early. We wait a few days and by May 11 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° | Apr 7 | Apr 3 | Mar 30 | Mar 27 | Mar 24 | Mar 22 | Mar 19 | Mar 15 | Mar 10 |
Last 20° | Apr 14 | Apr 9 | Apr 5 | Apr 2 | Mar 30 | Mar 27 | Mar 24 | Mar 20 | Mar 15 |
Last 24° | Apr 23 | Apr 18 | Apr 15 | Apr 12 | Apr 9 | Apr 7 | Apr 4 | Mar 31 | Mar 27 |
Last 28° | May 7 | May 2 | Apr 28 | Apr 25 | Apr 22 | Apr 19 | Apr 16 | Apr 12 | Apr 7 |
Last 32° | May 15 | May 10 | May 6 | May 3 | Apr 30 | Apr 27 | Apr 24 | Apr 20 | Apr 15 |
Last 36° | May 24 | May 20 | May 16 | May 14 | May 11 | May 9 | May 6 | May 3 | Apr 28 |
Data is provided by the NOAA National Centers for Environmental Information.