Terrifying Halloween forecast: Bay Area braces for coldest week since May

To beat the cold while knocking on doors to buy candy, strolling around a bar, or partying at an outdoor house party, costume designer Hester Michael of Hester's Designs in San Francisco's Excelsior neighborhood advises people to choose either one Choosing a costume that “keeps you warm”. Or find a base layer to wear under bib shorts.

“A gorilla suit could keep you warm,” she said. “I remember my mom making us wear sweaters under our costumes and it was horrible.”

So far this year, she's created a yellow motorcycle look that mimics Kill Bill, a family of characters from the Hot Dog on a Stick mall, and a Scream mask with kitten ears. She said people can feel cold on cold evenings even in full get-up and recommends “fleece-lined tights that look like you're wearing tights, or you can wear thermal tops, leggings and bodysuits.”

Marty Van Der Vert, owner of the 38-year-old, family-run One Stop Party Shop in San Francisco's Noe Valley neighborhood, doesn't think “people are worried about the cold or the rain” and will dress however they want.

“They could use coats or capes to cover themselves up,” she said. “I also have every mask from every movie you’ve ever seen. I have [Michael Myers from] Halloween, but I think I only have a few of these guys left. You name it. I have it.”

Flynn said temperatures will peak in the 50s in most locations over the next few days.

“That's pretty low for a high temperature, and when the trick-or-treaters come out, it's going to cool down even further,” he said.

“Last week we had about five degrees above normal; “This week we will be about 10 degrees below normal,” Flynn said.