Frost Dates: First and last frost dates for New Ulm, 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 19.
- There is a 50% chance of being hit by a 32° frost starting around September 28
- You have a 80% chance of seeing 32° by October 7
- 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 1 | Nov 4 | Nov 7 | Nov 10 | Nov 12 | Nov 15 | Nov 18 | Nov 23 |
First 20° | Oct 16 | Oct 22 | Oct 26 | Oct 29 | Nov 1 | Nov 5 | Nov 8 | Nov 12 | Nov 17 |
First 24° | Oct 5 | Oct 11 | Oct 16 | Oct 19 | Oct 23 | Oct 27 | Oct 30 | Nov 4 | Nov 10 |
First 28° | Sep 26 | Oct 1 | Oct 4 | Oct 7 | Oct 10 | Oct 13 | Oct 16 | Oct 19 | Oct 24 |
First 32° | Sep 15 | Sep 19 | Sep 23 | Sep 25 | Sep 28 | Oct 1 | Oct 4 | Oct 7 | Oct 11 |
First 36° | Sep 12 | Sep 15 | Sep 18 | Sep 20 | Sep 22 | Sep 25 | Sep 27 | Sep 30 | Oct 3 |
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 28. 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 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 2 | Mar 29 | Mar 26 | Mar 23 | Mar 20 | Mar 17 | Mar 14 | Mar 9 |
Last 20° | Apr 13 | Apr 9 | Apr 5 | Apr 3 | Mar 31 | Mar 29 | Mar 26 | Mar 23 | Mar 18 |
Last 24° | Apr 17 | Apr 13 | Apr 10 | Apr 8 | Apr 6 | Apr 4 | Apr 2 | Mar 30 | Mar 27 |
Last 28° | May 7 | May 1 | Apr 27 | Apr 24 | Apr 21 | Apr 17 | Apr 14 | Apr 10 | Apr 4 |
Last 32° | May 18 | May 12 | May 8 | May 5 | May 2 | Apr 28 | Apr 25 | Apr 21 | Apr 15 |
Last 36° | May 28 | May 22 | May 18 | May 14 | May 11 | May 7 | May 4 | Apr 30 | Apr 24 |
Data is provided by the NOAA National Centers for Environmental Information.