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