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