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