If you’re planning to spend time outdoors this weekend, you’re probably going to want to do that on Saturday, not Sunday. And don’t wait until late in the day on Saturday.

The weekend should get off to a beautiful start, according to the National Weather Service, with blue skies and a forecast high temperature of 56 on Saturday. But a strong cold front is expected later in the day, which will sweep into southern Utah by late Saturday night and drop temperatures by 20 degrees.

(Courtesy National Weather Service) A cold front will drop temperatures in Utah on this weekend.

And the NWS is predicting that snow will develop behind the cold front across northern Utah by Saturday evening, with some accumulation in both the mountains and the valleys along the Wasatch Front. Maybe even just in time for the Utah vs. California football game, which kicks off at 8 p.m. at Rice-Eccles Stadium.

After an overnight low of 29, the forecast high on Sunday is just 35 in the Salt Lake City area. There’s a 30% chance of snow showers before noon, with possible accumulations of less than an inch. Smaller amounts of snow are expected across southeast Utah on Sunday, and a mix of rain and snow is possible in the Lake Powell area.

And don’t expect any immediate warm-up. The NWS says “bitterly cold air originating over northern Canada” will stream south into the northern Rockies on Monday, and some of that “very cold air” will settle into parts of northern and eastern Utah.

The overnight lows Sunday through Wednesday will dip down to the upper-teens to mid-20s, with highs of 39 on Monday, 32 on Tuesday and 39 on Wednesday. Temperatures will rise into the mid-40s on Thursday — Halloween — but it’s expected to be chilly when kids are out trick-or-treating that evening.