Days are darker earlier. Nights are... nightier for longer.

It can only mean one thing: huge sales for lightbulb manufacturers.

Also: crab season is here.

Which brings us to Poppy’s Crab Shack, a new mobile operation serving up Dungeness crab up and down the coast, rolling out tomorrow.

This is huge: the next time you’re on Highway 1, you’ll be able to pick up fresh-off-the-boat crab the way it was meant to be eaten. (With reckless abandon.)

You know the drill. Follow them on Twitter. Then look for them at coastal locales south of the city from roughly Montara to Pescadero. (Say, Surfer’s Beach or the Half Moon Bay Airport.) Or just keep a lookout for a trailer with a logo of a big orange crab slapped on the side.

Your reward: whole, steamed crab that you’ll crack yourself and dip in full-cream salted butter. (It’s optional, but who are we kidding.) Other, more civilized forms: butter-poached crab sandwiches, panko-crusted crab cakes, creamy crab chowder and crab Louie.

Most of the operation is built for takeout, but they’ll occasionally park somewhere with picnic-bench seating. They’ll also do private events in the city proper, and they’re planning to hit SF full-on after the new year.

Great news for your resolution to eat more crab next year.