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