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