It seems hardly hyperbole to say that this weekend in Washington includes almost every sort of celestial, cultural and political observance and observation.

For one thing, even if politically this turns out not to be a time of change, we will still have a change of time.

That, of course, is the shift from daylight to standard time. It is far from the weekend’s only intriguing event. Blending them, we would seem to be in store for ghosts, ghouls and goblins disporting themselves beneath a full moon and amid suddenly chilly days and nights.

Saturday night is Halloween. This year’s celebration comes mere hours before that familiar clockwork sorcery revises the very look of our days and nights.

At 2 a.m. Sunday, while Halloween observance may yet be in full swing, the hour magically becomes 1 a.m. The sun will greet us an hour earlier Sunday morning, and it will abandon us to darkness an hour earlier Sunday evening.

Beyond that, Halloween may be observed here in the light of not merely a full moon, but an uncommon sort of full moon. According to the Farmers’ Almanac, a full moon has not appeared on Halloween in all of this country’s time zones since 1944.

This full moon may be of even greater rarity. It is a blue moon, a reference to being the second full moon in a single calendar month. With 29.5 days between full moons, it is not easy to fit them into any single month.

And Saturday morning may be our coldest in months, forecasts say. The National Weather Service issued a frost advisory that included the District.