The National Weather Service in Pendleton has issued a hard freeze warning for the Tri-City area from midnight through 9 a.m. Wednesday.
Temperatures will fall to near or below freezing by midnight and likely remain there until mid-morning Wednesday, forecasters said.
Temperatures are expected to be 22 to 28 degrees with some isolated colder pockets in the lower valleys, the weather service said.
Expect very cold temperatures again tonight with decreasing clouds and light winds that will allow strong cooling overnight and subfreezing temperatures.
A hard freeze warning means sub-freezing temperatures are highly likely for several hours.