What Conditions to Expect on Trails
From Oregon Hikers Field Guide
This is a general guide for what to expect on Oregon and southwest Washington 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. The Oregon and Washington Coasts as well as low elevation river hikes in the Coast Range and the Columbia Gorge may be good options. Duck hunting season closes at the end of the month.
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. Try some hikes in the Coast Range and at lower elevations in southwest Washington.
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, where the weather is often much clearer past Hood River. Many plateau level trails in central Oregon, e.g. along the Deschutes and Crooked Rivers, are accessible.
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. East of the Cascade Range, you can expect to hike up to 4,000 feet or higher. Options for long backpacking trips remain limited. Even on warm days swimming spots will be dangerously cold. Wildflowers bloom in central Oregon and the high desert. It's a good time for hiking the canyons below Steens Mountain, but there's still a lot of snow higher up. The Owyhee area is at its prime, but river crossings are deep and often unfordable, and road conditions can be poor because of rain storms.
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. Silver Star Mountain is mostly snow-free by now. This is the peak wildflower month at middle elevations in the Siskiyous and Blue Mountains. It is a good month for hiking the high desert (Pueblos, Trout Creek Mts., etc), but thunderstorms are common. The north section of the Steens Mountain Loop Road usually opens up by the end of the month.
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, the Three Sisters Wilderness, and the Wallowas are snow-free by the end of the month (if not sooner) but will be crowded on weekends.
August: High-elevation trails in the Oregon and Washington Cascades and the Wallowas 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. Huckleberries are ripe in Indian Heaven and around Mt. Hood and Mt. Adams.
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. If there hasn't been a lot of rain, huckleberries can still be good in the High Cascades. 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). However, this is a great time to be in the Wallowas, for example. Bow hunting season begins just before Labor Day, and some trailheads, e.g. the Elk Creek Trailhead on the west side of the Eagle Cap Wilderness, will see large parties with horses and mules packing into the high valleys.
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, Blue Mountains, Wallowas, and Steens Mountain. Weather is unpredictable with warm sunny days interspersed with cool rainy ones. Conditions may change unexpected during a hike, so be prepared. Deer hunting season begins in Oregon and Washington, but the timetables vary around the area. Waterfowl hunting season begins in earnest mid-month.
November: Most fall color is done by mid-month. Weather is mostly cool and rainy. High-elevation trails are often inaccessible due to snow. Snow becomes more likely in the Coast Range and Siskiyous. Low-elevation trails start becoming muddy. The elk and deer hunt is taking place in various units in Oregon and Washington. Wear bright red or orange when in the woods.
December: High-elevation snow renders mountain trails inaccessible for hiking. Hiking is limited to low-elevation trails in the Columbia Gorge and on the Oregon Coast. Weather is cool and wet.