I think it’s pretty obvious now, with daytime temps consistently rising into the 50s over the past several days, that we’re done with any kind of wintry weather for the season. So it’s time to pull the fork and say that WINTER IS OVER in the low to middle elevations of the Pacific Northwest, including the Columbia River Gorge.

This means that not only is arctic air completely out of the picture…but we also probably won’t see any more wet flakes flying in the lowlands, or near river level in the Gorge. In fact, I don’t think we’ll see more snow, anywhere below 2000′ elevation; the airmasses simply aren’t going to be cold enough.

Yes, I realize that we saw snow near sea level in 2008, both in late March and again in mid April. But events like that are rare flukes, and they are usually (though not always) one-day events.

This winter will be remembered mainly for one thing: the unusually cold 2nd half of February. Multiple snowstorms in Portland, and a nearly week-long arctic outbreak in the Columbia Basin and eastern Gorge? We haven’t seen anything like that in late February in a generation.

Even though the traditional calendar insists that winter continues until March 19/20…that definition seems pretty silly in the Pacific Northwest, unless you’re quite high in the mountains. It’s pretty tough to get arctic air to slide south into the Columbia Basin after February 20…and after March 1 it is extremely rare.

For official meteorological use, the word “Winter” normally means the 1st of December through the 28th/29th of February.

In fact, the normal coldest quarter of the year (both in terms of averages and cold/snow “events”), runs from roughly November 20 through February 19, a full month earlier than the astronomical definition of winter. Our daily average temps actually bottom out in late December! The same rule does NOT apply east of the Great Divide: in the Midwest and Northeast, the month of March can be very snowy (in some cases, snowier than January), and winter generally “peaks” later the further north and east you go.

Here is a map courtesy of ClimateCentral.com (http://www.climatecentral.org/gallery/maps/the-coldest-days-of-winter-in-one-map)

There are actually a fair number of places in the Upper Midwest, where February averages colder than December…whereas in our climate, February is (normally) the beginning of the transition from winter to spring.

Perhaps most telling of the different “experience” between here and the Midwest, though, is the comparison of the months November and March, the two “shoulder” months immediately before and after Winter. In our climate November is usually the colder of the two months; temps at DLS Airport average 42.6 F in November as opposed to 46.8 degrees in March. Compare this to Duluth, Minnesota – which is on almost the exact same latitude as The Dalles. Average temp in November is 28.75, versus 25.95 in March.

So while our winter is just barely getting started in late November and is fully over by March, for Duluth both months are in the ice box. And March is actually the colder and snowier of the two months!

…But why? In a few days I will discuss my own theory as to why winter peaks and ends, so early west of the Rockies. In the meantime, enjoy these mild days & cold clear nights! Tonight and tomorrow should be more of the same for The Dalles and Hood River; below freezing tonight and in the 50s again tomorrow.

Then Sunday-Monday we could jump into the 60s for the first time since early February….a clear sign that spring is truly here!