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