Temperatures are expected to drop to as low as 28 degrees in the Tri-Cities early Saturday morning.
The National Weather Service has issued a freeze warning for much of the Mid-Columbia from 1 to 9 a.m. Saturday.
A cold air mass is sitting over the region, with temperatures expected to drop lower as skies clear and winds diminish early Saturday morning, according to the weather service.
The low at the airport in Pasco is forecast at 30 degrees early in the morning, and the low at the Richland airport is forecast at 28 degrees.
The weather is expected to be cold enough to kill sensitive crops and other vegetation, according to the weather service.