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