Oregon Frost Alert: Willamette Valley and Cascade Foothills May See Damage to Plants Until 9 a.m. Tuesday

Gardeners and growers across northwest Oregon are being warned to prepare for potentially damaging frost overnight, as temperatures are expected to dip into the low 30s. The National Weather Service in Portland has issued a Frost Advisory from midnight until 9 a.m. Tuesday, affecting much of the Willamette Valley, Cascade foothills, and neighboring regions. Forecasts indicate temperatures between 33°F and 36°F, which could lead to widespread frost formation, especially in areas above 500 feet in elevation. Communities likely to be affected include the Tualatin Valley, outer southeast Portland metro, and the Columbia River Gorge. Parts of southwest Washington, including Cowlitz and North Clark counties, are also under the advisory.

Gardens, Crops at Risk as Temperatures Drop

The cold snap comes at a critical time for the region’s gardens and farms. Many residents have already started spring planting, making tender crops, budding flowers, and early fruit trees especially vulnerable to frost damage. Affected counties include Benton, Linn, and Lane, which are home to both rural farms and residential gardeners. Cities such as Salem, Eugene, Hillsboro, and Longview are expected to experience frost-prone conditions, especially in outlying or elevated areas. The NWS warns that sensitive vegetation could be harmed or killed if left exposed overnight. To protect plants, residents are advised to bring potted plants indoors or use breathable coverings like bedsheets, thin blankets, or frost cloths to trap ground heat. Avoid using plastic covers directly on plants, as they can retain moisture and cause freezing damage.

Late-Season Chill Echoes Past April Cold Snaps

While frost in April isn’t unusual, the timing is especially inconvenient given the recent stretch of mild spring weather. This has encouraged many to start planting early, increasing the number of vulnerable plants outdoors. Historically, April frosts have led to agricultural losses, particularly in elevated and rural areas of Oregon. Growers in these regions should stay especially cautious, as even brief frost exposure can damage early fruits and vegetables, reducing crop quality and yield.

More Cold Possible Later in the Week

The immediate frost threat is expected to subside by mid-morning Tuesday as the sun rises and temperatures rebound. However, the National Weather Service warns that cold air may linger through the week, meaning additional frost advisories could be issued. Residents and farmers are urged to monitor local forecasts closely and remain prepared for more cold nights. Staying proactive can make a significant difference in protecting both home gardens and larger crop investments from unexpected temperature drops.