Apparently flipping the calendar from April to May hasn’t helped Central Washington shake unusually cold overnight temperatures.

The National Weather Service’s Pendleton (Ore.) office issued a freeze warning for 2 to 9 a.m. Monday, May 9, with sub-freezing temperatures of 30 to 32 degrees expected for “cold prone areas” of the Kittitas and Yakima valleys.

Frost and freezing temperatures can kill crops, other sensitive vegetation and possibly damage unprotected outdoor plumbing, the NWS states.

More sub-freezing temperatures are possible the next two nights as well, the weather service states. Patchy frost is possible Tuesday and Wednesday mornings.

The Weather Service predicts sunny skies with windy conditions Monday, with a high of 60 degrees. Northwest wind gusts could reach 21 mph Monday night. High temperatures for the week will remain in the low 60s, with a 50% chance of rain predicted Thursday, May 12.

In its freeze warning, the NWS advises taking steps to protect plants from the cold. To prevent freezing and possible bursting of outdoor water pipes, they should be wrapped, drained or allowed to drip slowly, the NWS advised.