As if to amuse people who live in more northern climates, the Washington region went into headlong retreat Friday before the first flake fell in a snowstorm that threatened to amount to the depth of a peanut butter and jelly sandwich.

The snow fluttered in at midafternoon, dancing about with the ambivalence of a child bound for the school bus, as if unaware that its threat had sent thousands of yellow buses filled with children home early. Even as they picked up the pace, the flakes seemed puny and incapable of conspiring to behave anything like a blizzard.

The major roads, treated in advance and muscled into submission by squadrons of salt trucks and plows, remained clear. Homeward-bound commuters left early in droves, making the evening rush hour less fearsome than it might have been, and many office workers never bothered to leave home at all Friday.

Monday was the last day this month with a temperature that was above normal for the date.

Jason Samenow, chief meteorologist of The Washington Post’s Capital Weather Gang, said the last of the snow would fall well before midnight Friday.

The reaction to winter weather was another reminder that though Washington has the Type-A intensity of the North, its snow sensibilities are distinctly Southern.

“Come on, people!” said Mimi Newcastle of Fort Washington, who grew up in snowy Illinois and Wisconsin. “You don’t start asking if things are canceled when there isn’t even any snow falling.”

But cancellations will continue into the weekend, although the amount of snow that fell in most areas could be swept away with a broom.

In Prince George’s County, Saturday’s College Board SAT testing was rescheduled to Feb. 26. The College and Career Preparatory Conference and evening high school registration have been moved to Feb. 2. School officials said all other Saturday activities will start at noon.

In Loudoun County, the Boy Scouts canceled the appropriately named “Freeze-O-Ree,” though their communications director, Michael J. Sierra, reported they “were all for still having the camp-out.”

“They had laid out their mukluks last night and were calling around about renting a team of dogs and a sled,” Sierra said. “Unfortunately, the county officials beg to differ and frown on the prevalence of frostbite,” he said.

With some snow and ice still on the ground from Thursday, school officials throughout the region were the first to react to the threat of an inch or two of new snow. Those interviewed cited a need to put safety first and to let any error be on the side of caution.

They also said they had consulted widely before deciding, seeking views from such sources as the weather service, their local governments and even other school systems.

Fairfax County spokeswoman Merni Fitzgerald cited the difficulties of deciding for a jurisdiction of nearly 400 square miles, where conditions may differ from place to place.

“Safety is the paramount concern,” Fitzgerald said.

The system decided to close schools two hours early Friday and canceled afternoon and evening activities.

Jeffrey Platenberg, the county’s s new assistant superintendent for facilities and transportation services, who started Jan. 8 after working in Loudoun, said it was important to consider safety, including that of teenage high-schoolers who may not be as experienced driving in slippery conditions.

On Friday, Fairfax County Executive Edward L. Long Jr. decided to keep the government open, while encouraging parents with school-age children to use personal leave.

Pam Konde, the mother of three children in Fairfax County schools, said the early dismissal was no inconvenience.

“If it means we have a safer drive home for our kids and less buses on the road during a snowy commute home for everybody on a Friday afternoon, then I’m fine with that,” Konde said.

In Prince George’s, school system spokesman Briant Coleman said,“We just want to make sure our students, teachers and staff get home safely.”

“It’s out of an abundance of caution that we made the decision to dismiss two hours early,” Coleman said.

In Montgomery County, which closed early, schools spokesman Dana Tofig said, “The biggest concern that we have is the heaviest snow is supposed to fall when our buses would have been rolling,” before streets could be treated.

“We always err on the side of keeping our kids safe and our staff safe.”

Loudoun schools decided to dismiss an hour early.

In Prince William County, the decision to close an hour early was made as the forecast worsened and precipitation was expected earlier in the day. The call was difficult, said spokesman Phil Kavits, but officials try to err on the side of safety. 

Arlington County and Alexandria public schools canceled Friday ­after-school activities.

“It’s going to snow this afternoon, so everyone in the city will hate me or love me, no in-
betweens,” Morton Sherman, superintendent of Alexandria school system, said Friday. They’ll ask him, he said, only half-joking, “Why don’t you cancel school? Do you hate kids?’”

Emma Brown, Lynh Bui, Susan Svrluga and Ovetta Wiggins contributed to this report.