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