Astronomical spring, based on the orbit of the Earth, is here, but psychological spring, based on comfort, may not be. It can be delayed, as was demonstrated Friday when the coldest morning all month arrived in Washington.

It was only 28 degrees at Reagan National Airport on Friday morning. It was only the fourth subfreezing day there all month, the first below 30, and the coldest day since Feb. 21.

But it is spring nevertheless. Astronomical spring, marked by the vernal equinox, started Wednesday morning. It depends on the movement of the Earth around the sun and the tilt of the planet’s axis, and not on any thermometer at National, or at Dulles, where it was 25 on Friday.

Such readings seemed to justify unspringlike forecasts suggesting a chance of snow in the Washington region sometime before Tuesday. Not much and perhaps none close to the city, but maybe a few flakes in a few places.