It’s time for holiday cheer around the fire, sweaters in the snow and cozy gatherings out of the winter wind.

It’s also just about time for T-shirt temperatures for millions of Americans, who will face seesawing weather that could both disrupt their travel plans and scramble their suitcase packing.

Nearly 120 million people are expected to travel at least 50 miles by plane, car or another mode of transportation between this Saturday and New Year’s Day, according to projections from AAA, whose experts expect this year to see the most December holiday travel on record. Almost 90 percent of people traveling are expected to drive, and another 7 percent are expected to fly. This demand alone would normally snarl travel, and with some precipitation possible on the East and West Coasts in the coming days, many are likely to face delays.

Here’s a look at the days leading up to Christmas, and where weather could disrupt your trip.

Thursday: If you’re heading out early you may face storms.

A quick-moving storm system pushing across the northern Plains overnight is expected to begin sweeping through the Midwest and the Great Lakes region. Some moderate to heavy snow may fall, particularly across portions of northern Wisconsin. While snow is not uncommon for the region, it may cause some minor inconveniences, and there is at least some risk of it creating hazardous driving conditions.

By Thursday evening, another weather system in a long series of back-to-back storms will bring a risk of rain to much of the Pacific Northwest. While travelers are used to wet weather there, this region is likely to see some of the nation’s worst weather over the holiday, with periods of heavy rainfall and snow through Christmas Day, said Ashton Robinson Cook, a meteorologist with the Weather Prediction Center.