February colder than January

[nei]

Originally Posted by MeteoFlan

No it doesn't I've also wondered why their February seems to get warmer that quickly. Maybe their prevailing wind comes from a different direction than straight over the sea during those months. They are quite a bit south of us latitude wise and have a lot more sun hours in February than we do so could also be to do with stronger sun and more sun hours then making the temperatures rise quicker.

I think the airflow is from the sea still. I think above 40°N or so sun is still too weak in February to have much warming effect; airflow still dominates. Check out this station along the coast:

ASTORIA RGNL AP, OREGON - Climate Summary

February is warmer than December, January is barely colder than December. But notice the precipitation is less in February, and probably also cloudiness. My guess is the sun angle makes a bigger difference because sunshine is increasing. If it were sunshine though, the lows wouldn't increased.

In southern and central California, precipitation peaks later but February is still slightly warmer than December. But maybe it's south enough for sun angle to make a difference? I think the cause is the Pacific Ocean doesn't have the usual lag mid latitude oceans do, the sea is partially cooled by upwelling strength rather than just a delayed response to the sun. From December to May, the sea temperature changes only 1°F:

https://www.nodc.noaa.gov/dsdt/cwtg/all_meanT.html

see central coast, with the minimum often in April. That's not enough to cause much lag. Some stations have rather mild summer sea temperatures; this is because they're facing a bay (most the San Francisco Bay) which doesn't get affected by the cold current and upwelling. Trinidad, CA has the same beach temperatures in July and early August as December! The Pacific: North has a bit more sea temperature lag, but still not much (2-3°F). Again, Astoria is obviously facing a bay; 68°F is an implausible pacific ocean temperature except Los Angeles and southward. If you look at Atlantic: North there's more sea temperature lag. And usually for New England the arctic blasts from the north are harder to reach, that's influenced by the sea but just continental lag (little sun in the subarctic, so in early winter it's not cold enough bt there).