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