Frost Dates: First and last frost dates for Port Orford No, 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 May 30. 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 March 23, so we don't dare plant that early. We wait a few days and by April 19 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° | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Last 20° | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Last 24° | Jan 25 | Jan 3 | -- | -- | -- | -- | -- | -- | -- |
| Last 28° | Mar 10 | Feb 22 | Feb 9 | Jan 29 | Jan 19 | Jan 7 | Dec 23 | Nov 26 | -- |
| Last 32° | May 2 | Apr 13 | Mar 30 | Mar 18 | Mar 7 | Feb 24 | Feb 12 | Jan 29 | Jan 10 |
| Last 36° | May 30 | May 16 | May 6 | Apr 27 | Apr 19 | Apr 11 | Apr 2 | Mar 23 | Mar 9 |
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 November 14.
- There is a 50% chance of being hit by a 32° frost starting around November 30
- You have a 80% chance of seeing 32° by December 16
- 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° | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| First 20° | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| First 24° | Dec 19 | Jan 15 | -- | -- | -- | -- | -- | -- | -- |
| First 28° | Nov 16 | Dec 1 | Dec 12 | Dec 22 | Jan 1 | Jan 12 | Jan 27 | -- | -- |
| First 32° | Nov 6 | Nov 14 | Nov 20 | Nov 25 | Nov 30 | Dec 5 | Dec 10 | Dec 16 | Dec 26 |
| First 36° | Oct 16 | Oct 23 | Oct 28 | Nov 1 | Nov 5 | Nov 9 | Nov 13 | Nov 18 | Nov 25 |
Data is provided by the NOAA National Centers for Environmental Information.