PORTLAND, Ore. (KOIN) – If you were thinking we were just going to have a quiet weather week, you’re mostly correct. However, there is one thing that may start to show up this week and that is some patchy frost around the Willamette Valley. The chance that we see some in Portland is pretty low, but it’s possible for some of the outlying areas to see some frost develop.
Last year, we had our first freeze come the day before Halloween. Temperatures dropped to 29 degrees, which was our first time hitting 32 or below last fall. On average, we tend to see our first freeze around mid November, that date is November 15. However, there will be some neighborhoods in the 30s come Thursday morning. The earliest freeze on record came on October 8, 1985. I figured I throw a few snow stats into the graphic as well, so if you were thinking snow, the earliest we’ve even seen a trace of snow at the airport falls on November 3, 1973. Let’s hold off on that thought for the meantime.
Now Tuesday morning is going to start in the 40s with some clouds. That is actually where we should be for this time of the year. The average low this time of October is actually 45 degrees. This month has been quite mild overnight. That cold air starts to move in by the latter section of the work week though. By Thursday morning, there will be some locations flirting with the mid 30s in the valley.
With that cold air settling in, a Freeze Watch will be in effect late Wednesday Night through Thursday Morning for locations south of Eugene. It’s possible we see some alerts pop for other areas of the state when we have a better gauge of how cold it’s going to get. I would say it’s those areas like Hillsboro that would have a chance. The threat for frost is higher for the Cascade foothills. By the weekend, after another wave of cold air moves in, we may have a chance closer to Portland.
Here is a photo of some patchy from from last fall. Notice the color of the leaves, it’s definitely a bit later in the month.