Frost Dates: First and last frost dates for Red Wing Dam, 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 3
- You have a 80% chance of seeing 32° by October 12
- 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 27 | Nov 2 | Nov 7 | Nov 10 | Nov 14 | Nov 17 | Nov 21 | Nov 25 | Dec 1 |
First 20° | Oct 20 | Oct 25 | Oct 30 | Nov 2 | Nov 5 | Nov 8 | Nov 12 | Nov 16 | Nov 22 |
First 24° | Oct 9 | Oct 15 | Oct 19 | Oct 23 | Oct 26 | Oct 29 | Nov 2 | Nov 6 | Nov 12 |
First 28° | Sep 27 | Oct 2 | Oct 6 | Oct 10 | Oct 13 | Oct 17 | Oct 20 | Oct 24 | Oct 30 |
First 32° | Sep 18 | Sep 23 | Sep 26 | Sep 30 | Oct 3 | Oct 5 | Oct 9 | Oct 12 | Oct 17 |
First 36° | Sep 14 | Sep 18 | Sep 21 | Sep 23 | Sep 26 | Sep 28 | Sep 30 | Oct 3 | Oct 8 |
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 29. 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 29, 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 8 | Apr 2 | Mar 30 | Mar 26 | Mar 23 | Mar 20 | Mar 17 | Mar 13 | Mar 8 |
Last 20° | Apr 13 | Apr 8 | Apr 5 | Apr 2 | Mar 31 | Mar 28 | Mar 25 | Mar 22 | Mar 18 |
Last 24° | Apr 23 | Apr 18 | Apr 15 | Apr 12 | Apr 10 | Apr 7 | Apr 4 | Apr 1 | Mar 27 |
Last 28° | May 4 | Apr 28 | Apr 24 | Apr 20 | Apr 17 | Apr 13 | Apr 10 | Apr 5 | Mar 30 |
Last 32° | May 22 | May 15 | May 10 | May 5 | May 1 | Apr 27 | Apr 22 | Apr 17 | Apr 10 |
Last 36° | May 29 | May 23 | May 18 | May 14 | May 11 | May 7 | May 3 | Apr 29 | Apr 22 |
Data is provided by the NOAA National Centers for Environmental Information.