It is the end of November, and until a few days ago, large areas in western Washington had not yet to experience temperatures of 32F or below. But that situation is now over....frost has returned to Seattle, Bellingham, and some other locations near Puget Sound.
It is interesting to plot the average day of first freeze over the region (NOAA map, below).
Over the higher elevations east of the Cascades, the first freeze generally occurs in September.
October brings freezing conditions to the lower elevations in eastern Washington and lower elevations away from the water over western Washington.
Early November beings freezing over much of the lowlands of Western Washington and Oregon, and late November for some Puget Sound locations and coastal Oregon.
December on the southern Oregon coast.
Consider recent temperatures at a few local reporting stations during the past few months.
At Seattle, yesterday (Thursday) morning was the first to hit freezing (horizontal blue line). Same with Bellingham. Seattle and Bellingham are warmed by the proximity to mild water surfaces.
In contrast, Olympia, which is distant enough from the water to have a more "continental" climate, several days have reached freezing during October.
But if you really like early frosts, head over to eastern Washington, where the warming influence of the Pacific and Puget Sound are greatly attenuated.
For example, in Yakima, from late September forward, many days this fall have hit the freezing mark and below.
Similar situation in the Tri-Cities (Pasco shown below).
What is the frost forecast for the next week?
High pressure will building over the eastern Pacific and western WA locations like Seattle will progressively warm, so no frost in the forecast and progressive warming (an ensemble of many forecasts is shown below).
In contrast, cold, dense air will remain within the Columbia Basin for a long time, with Yakima enjoying temperatures in the upper 20s for a while.
Good for making ice wine perhaps.😀😋
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While Bellingham is situated along the coast of the Georgia Basin, it’s physiographically part of the Fraser lowland and exposed to bitterly cold Fraser outflow - of which has there has been none to speak of this season. Not only was Bellingham’s first freeze of the season the latest on record, by this time of the year, on average, it’s already dropped into the mid-20s. So far, there’s been no cold weather at all and the minimum temperature of the season to date is a mere 32F - quite unusually warm for “the icebox of Western Washington”. Based on the latest CPC outlooks it appears as though winter will continue to be indefinitely postponed :(.
ReplyDeleteEven SeaTac’s first freeze was 2-weeks late and most of the city has failed to drop to the freezing mark including the NWS Seattle WFO and Boeing Field. While first freezes of the season in December aren’t unheard of at these typically warmer locations, they are certainly considerably later than normal.
An interesting aspect of our non-winter so far is that monthly average temperatures are not notably above normal. It hasn’t been particularly warm - rather there’s been an unusual (unprecedented, in some cases) lack of cold.
Bellingham is a hybrid...most of the time the Fraser outflow has little effect on Bellingham..cliff
DeleteFriend: Given that weather doesn't ever arrive on a schedule in the PNW (like trains and planes are supposed to), I would have a hard time saying that a first frost anywhere is "early" or "late."
DeleteBLI's (Bellingham's airport's) micro-climate is highly uncharacteristic of the general area's ("physiographic") conditions, so I question how meaningful the "first frost" calendar-date statistic is. Weather varies widely within "climates". I've kept records including "first frost" and "first snowfall" for nearly 50 years mid-county. As an "east ender" who has commuted to Bellingham almost daily over that timespan (to work, and also to golf), I know first-hand that the Bellingham "banana belt" weather differs widely from the adjacent weather patterns. This irregularity is widely known.
I've looked through the overnight low data 2014 forward (the most recent 11 years) for this valley location that's mid-county, elevation less than 1000 ft. First frosts have been: 2014-Nov 10, 2015-Nov 9, 2016-Oct 11, 2017-Oct 14, 2018-Oct 3, 2019-Oct 9, 2020-Oct 24, 2021-Oct 12, 2022-Oct 23, 2023-Oct 28 (was actually 32F or lower for 7 days, well into the low 20's!), 2024-Nov 16. First snow here (2024) was Nov 18. I could cough-out all sorts of data re snow here, including 'first mountain snow" which has been as early as late August and early September some years. I observe and maintain these records because weather is a curiosity (and it relates to long-term study of precipitation-temp regarding streamflow). If there's any trend at all regarding "lows", if anything I'd say very cautiously, "There has recently been a cool trend (2016-2023 had October first-frosts, many nights in the 20's here)
but these weather patterns are very big and complex. I bet a dollar (maybe a dime) on what's going to happen Dec-March in the Cascades, but the ski season's off to a good start at Baker.
Friend: Errata for this year's (2024) first frost date here: Oct 25, 30.6 F. I double-checked my records - that was a typo. I also meant to type "I would NOT bet a dollar..." on predictions based on statistics like "average monthly" or (gasp) state averages. Sorry about that typo.
DeleteGlacierBake,
DeleteThank you for the response - and what an excellent opportunity to compare with the available data for KBLI:
2014: November 13
2015: November 10
2016: October 12
2017: November 2
2018: November 7
2019: October 9
2020: October 25
2021: November 1
2022: November 1
2023: October 26
2024: November 28
Based on the data you provided, your first freeze of the season was, on average, 11 days earlier than KBLI for the 2014-2024 period.
KBLI: October 31, Glacier: October 20.
Whether a first or last freeze is notably early or late is easily determined based upon the available data. The characterization of this year's first freeze at KBLI as unprecedentedly late is simply a statement of fact because it is indeed the latest first freeze in that site's nearly 80 year period of record.
Regarding KBLI's supposed anomalously warm microclimate relative to the rest of the Fraser Valley physiographic region, the "Clearbrook" weather station, located near Sumas had an average first freeze date of October 27 for the aforementioned 10-year period in question. That's barely a handful of days earlier than for KBLI. If we look at the data for Blaine, the average first freeze date during the period in question is November 7. Your insistence that KBLI sports a climate which is exceptional compared to other locations in the lowlands of Western Whatcom County does not hold up to scrutiny.
With regard to comparisons of Bellingham's climate with that of Glacier, the only point would be to illustrate that they have substantially different weather - it'd be like comparing apples to banana belts! In reality, it's Glacier, the last outpost of civilization along the Mount Baker Highway, which has a climate that is exceptional by the standards of the more populated parts of the county to the west. Blaine, Ferndale and Lynden have climates which are considerably more similar to Bellingham's than to Glacier's.
For any given region in the PNW (e.g. SeaTac), is there a historical plot of the date of the first frost in a calendar year? Any trend?
ReplyDeleteNo freeze yet in Gig Harbor!!
ReplyDeleteI'm still seeing plenty of random yellow flowers when I go out to ride along the centennial trail. Last winter, most of the flowers had capitulated by this point but some did hang on until around the middle of the month. I'm guessing this year will be no different and maybe - just maybe - the flowers will make it until Christmas or new year's day.
ReplyDeleteWe had our first frost in Prineville back in the middle of August, if II recall correctly. It got down to 12 lasts night.
ReplyDelete