What Conditions to Expect on Trails
From Oregon Hikers Field Guide
This is a general guide for what to expect on Oregon hiking trails throughout the year. Please remember that every year is different. For example, a warmer drier winter means that wildflowers will bloom earlier and summer wildfires may be more abundant, whereas a cool wet winter with an above average snowpack can delay wildflower blooms and make stream crossings dangerous in early to mid-summer. Rain is possible any day of the year, even in summer. Check recent trip reports on this site for the latest conditions. Weather conditions may change unexpectedly during any hike, so preparation is very important.
January: Only low-elevation trails (2,000 feet or lower) will be accessible. Weather is cool and wet and possibly even snowy. In the event of snow at low elevations, trails may be inaccessible or dangerous. Accessible trails are often muddy.
February: Only low-elevation trails (2,000 feet or lower) are accessible. Weather is cool and wet and possibly even snowy. In the event of snow at low elevations, trails may be inaccessible or dangerous. The earliest wildflowers start blooming in the eastern Gorge, generally near the end of the month. Accessible trails are often muddy.
March: Weather is usually cool and wet, but warm sunny days are possible. Trails above 2,000 feet elevation may still be under snow. More wildflowers will be blooming at low elevations in the eastern Gorge.
April: Weather is unpredictable, as warm sunny days are interspersed with cool rainy ones. Weather conditions may change unexpected during a hike, so preparation is very important. Wildflowers becoming quite abundant in the Gorge as the month progresses. Continued snow accumulation in the Cascades is likely.
May: Weather is improving with higher likelihood of sunshine but plenty of rain is still possible. Weather conditions may change unexpectedly during a hike. Wildflowers are abundant at locations in both the western and eastern Gorge. Hiking is still mostly restricted to 3,000 feet elevation or lower. Options for long backpacking trips remain limited. Even on warm days swimming spots will be dangerously cold.
June: Higher-elevation hikes start becoming accessible as the snow melts (depending on snowpack and weather). Even on warm days swimming spots may be dangerously cold. Alpine areas are likely to remain snow-covered. Trails in the Cascades may have suffered damage from winter storms and therefore may be impassible.
July: Most high-elevation hikes in the Cascades are snow-free by the middle of the month. Mosquitoes can be abundant in the mountains, especially shortly after the snow has melted. Weather is usually warm and sunny, but rain is always possible. Scorching hot weather is also a possibility. Popular backcountry areas such as Jefferson Park and the Three Sisters Wilderness are snow-free by the end of the month (if not sooner) but will be crowded on weekends.
August: High-elevation trails should now all be snow-free. Daytime temperatures can get quite hot, even at high elevations. Rain remains possible. Long-distance visibility will frequently be lessened due to wildfires. Trails and roads may be closed due to wildfires. Campfires may be banned if conditions are hot and dry. Popular backcountry sites will be very crowded on weekends.
September: The days are getting shorter and cooler but the weather is generally still good. Crowds on trails are diminished, especially on weekdays. Long-distance visibility may be lessened due to wildfires. Trails and roads may be closed due to wildfires. Fall color arrives in the mountains during the second half of the month. Night temperatures at backcountry sites may dip into the 40s (or lower).
October: Fall color is abundant at lower elevations, and arrives in the Gorge late in the month. Snow becomes a strong possibility in the Cascades. Weather is unpredictable with warm sunny days interspersed with cool rainy ones. Conditions may change unexpected during a hike, so be prepared.
November: Most fall color is done by mid-month. Weather is mostly cool and rainy. High-elevation trails are often inaccessible due to snow. Low-elevation trails start becoming muddy.
December: High-elevation snow renders mountain trails inaccessible for hiking. Hiking limited to low-elevation trails. Weather is cool and wet.