September 19th, I just walked out with the doggie to find the windshield frosted over and the grass blades coated the same. The norm is first frost around the half of of October.
Not like it means anything other than it is time to bring my lemons in. Looking at the extended forecast it looks like is going to be the norm; high in the 50’s lows in the 40’s for the next 10 days. I’m probably not going to mark this as the official first frost.
I’m surprised frost doesn’t come earlier if you’re way up in Alaska. You must be somewhere near the coast?
Early to mid October can be a tossup in BC. Last year it was warm and sunny through most of the month. But no matter what, we always seem to have freezing cold weather for taking the kids out trick or treating on Halloween.
its came close a few times here getting in the upper 30’s at night starting in early sept. wont be long now. hard killing frosts are usually late oct.
I’m a bit curious how people define ‘frost’ in different parts of the US and the world really. For me a frost is when you have ice form on surfaces like cars, roofs, grass.
For my area (deep south), a large number of our frosts occur when the measured temp (at 6 feet elevation) is above freezing. The frost forms from good radiation and saturated air on those surfaces but it’s warmer above it. Keep in mind I may only get 10-20 actual freezes in a winter.
In England they refer to freezes as frosts I believe, but it’s a bit confusing for my time spent there. They actually report 2 temperatures in England (the whole of the UK I believe). Ground surface and air temperature.
We’ve been lucky so far. Our earliest frost can come as early as the end of August. But if we get past that we may go into October without one. If NOAA is right we might be good for another week.
I don’t know, I think frost is defined the same way the world around. The only caveat would be that the visible frost is just a side effect of the temperature dropping to/bellow the freezing point of water, so I guess if it is dry enough you can have a freeze without frost.
There is also the fact that you could have frost above 32f. Cold air sinks, so in still nights with little air movement ground level air can be cold enough for frost to form without the overall temperature dipping that low.
Needs to be nearly no air movement for frost…even if temps drop under 32 degrees.
First frost in Kentucky in my lifetime? Sept. 18, 43 years ago. I expect mid October.
No cold air drainage here as we have no terrain…
When you face a fire you can feel the heat on your face from the radiation. If you turn around in place, your face feels cooler. The air temperature around your face is the same. That’s the kind of magical effect of radiation. Radiation is a surface phenomena.
The same occurs in the opposite direction on a clear, calm night. Surfaces can get colder than the air above it. Black body radiation to be nerdy. Some surfaces are better black bodies for more efficient radiation.
The frosts here where I live are almost always at above freezing air temps… Mostly because we don’t get all that cold here in winter. It’s very common when it’s well below freezing to not have any frost…which seems a bit strange, but then we get that cold only a few times a year and there is often a lot of air mixing above the surface which inhibits radiational cooling so we don’t get the dew formation.
Anyway it’s all interesting.
I like the reporting of ground and air temps though…
about the same here. prior to the late 80’s we had frosts in late aug.
Average first frost in much of central MN is about now. This year, we’ve only come close once or twice. No 30s in the 10 day forecast, so maybe we’ll make it all the way to October.
This thread got me to look up freeze maps, looks like most of the lowlands around the Salish Sea are early-mid-November as average first 32°F night, which is what I think many people mean when they talk about historical “first frost” climate records.
You can find all sorts of interesting other maps on the MRCC/VIP website related to freezes, like latest first frost, latest last frost, etc.:
And PlantMaps has the immediate Seattle area more like mid-late November:
1980 gave earliest frost…1987 gave me my latest going back 50 years of taking note of these things.
((For the record 1980 also my hottest July…but it got chilly Sept. 18, 19 that year.))
So far have seen 51 for a low here this month. Looks like mostly 50’s next 14 nights.
I’ll take it…except for need to water containerized plants … I like current conditions, nice 80/54 or so.
Okra vs Figs, Raspberries…
A light frost will take out your okra… it thrives in heat but is cold whimpy.
Figs and Raspberries here often continue to produce after okra is done… but i call it a hard frost when it takes those out.
Last year we had a hard enough frost early in Nov to take all 3 out.
A few years back my okra gave up mid Nov… but figs and raspberries continued to produce until Dec 3.
That is the latest hard frost that i can remember here.
