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