Cold front to chill Bay Area.

A cold front sweeping down from Canada is expected to bring snow to the Santa Cruz Mountains and unusually chilly nights to the Bay Area, with below-normal temperatures posing a threat to elderly people, pets and plants.

Starting Sunday night and continuing for a week, frigid air is expected to blanket the Bay Area, including the East Bay and North Bay, with the coldest temperatures hitting early Tuesday morning, National Weather Service forecaster Steve Anderson said.

The weather service has placed most of the Bay Area under a freeze alert starting Monday at midnight and ending Tuesday at 9 a.m. That warning may later be extended, Anderson said.

Exempt from the freeze alert are San Francisco and the Peninsula south to Mountain View, along with Santa Cruz and Monterey, Anderson said. “It will be cold but not as cold as the other surrounding areas,” he said.

Early Monday morning is expected to bring temperatures approaching freezing in some North Bay spots, while most of the Bay Area will see lows in the upper 30s to low 40s, Anderson said. The coldest temperatures will likely come between 4 a.m. and 7 a.m. Monday through Wednesday.

On early Tuesday morning, the mercury across much of the region is expected to plunge, with Cloverdale, Calistoga, the East Bay, Morgan Hill and Gilroy seeing temperatures in the high 20s, and San Jose seeing a low around the freezing point of 32 degrees.

Combined with scattered showers — possibly heavy at times — expected Sun-

day night through Monday morning and on Wednesday, the cold snap will likely bring a dusting of snow to the Santa Cruz Mountains, possibly to as low as 1,000

feet above sea level, Anderson said. Snow may fall on Highway 17 on Sunday night and early Monday morning, creating a driving hazard, he added.

Any water on roadways could freeze during the coldest times, and snow at higher elevations could make driving perilous. The

East Bay hills, however, will probably see little or no snow because negligible precipitation is expected there, Anderson said.

The origin of the cold snap — Canada — could be galling for patriotic Americans watching the 2018 winter Olympic Games. By Sunday afternoon, Canada had 16

medals to the United States’ 10. “They’re beating us in the Olympics and now they’re just going to give us some cold air,” Anderson said.

Because the coldest periods will likely last for several hours, plants may die, pets should be brought inside or given appropriate shelter, and older residents

could be in danger, Anderson said.

“If you want to check on people you think might be at risk, it’s best to check before nightfall to make sure they’re OK for the morning,” Anderson said.

Forecasters are predicting daytime highs in the 50s through the weekend.

Compared to average temperatures, the coming days’ highs will be slightly cooler than usual, but night-time and early-morning lows will be up to 10 degrees below normal, Anderson said.