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