Temperatures on the PNT can vary greatly with summertime highs in the 80s and 90s in the daytime, and cooler, sometimes freezing, temperatures at night. Dressing in layers and being prepared for hot dry sections of trail, as well as cold wet sections, will by the key to having a comfortable and safe trip on the PNT.

Rain in the Northwest is often accompanied by a cold front, making for chilly or windy conditions where hypothermia is possible. Even long after rains have stopped, trail-side brush and large-leaved plants, like thimbleberry, continue to transfer moisture to clothing. In the mountains, heavy, cold rain or snow can fall anytime of the year, but does more frequently during the shoulder seasons and winter.

Although some PNT thru-hikers have experienced little rain during years of drought, it is also normal to experience periods of cold wet weather on the PNT. A light, breathable rain jacket is highly recommended for any trip on the PNT.

Due to the risk of hypothermia on the PNT, a durably waterproof storm shell is recommended over a basic polyurethane model. These products come at a higher price, but typically are more breathable and far more durable than a basic model, being constructed of thicker nylon shell fabrics. During bushwhacks and scrambles, heavier fabrics are less likely to become torn.

All waterproof fabrics work best when clean. Consider washing soiled rain gear with an appropriate cleaner if the face fabric does not bead properly. Some thru-hikers plan ahead by mailing themselves special soap so they can wash their gear mid trip to ensure good performance.

Also consider packing bottoms, such as rain pants or a kilt, to protect against wet brush and wind. Most backpacks are not completely waterproof on their own.  Keeping the contents of your pack dry is of critical importance.  This can be accomplished with a pack cover, a pack liner (odor-free trash compactor bag), or waterproof stuff sacks.

Due to stream crossings, wet brush, snow or rain, your feet will get wet no matter what. Warm socks, which insulate when wet, like wool or possum down, will help you stay reasonably comfortable until you can change into warm, dry clothing in camp.

The weather window recommended for long-distance hiking on the PNT typically opens in early summer (mid June) and closes in late summer (September). Annual variations in amount of snowfall will affect the weather window from year to year. 

In the Northwest, the transition from mild weather in summer, to severe winter weather in fall, can happen very suddenly. Early fall storms can bring feet of snow, or cold heavy rain, which make backcountry conditions more difficult. Snow and ice can make steep trails dangerous, even impassable.

Outside of this “window” the weather in the Northwest also becomes much wetter, more extreme and unpredictable. Snowfall and high winds can occur more frequently in the mountains.

Snowpack, which is at its peak in May in the Rocky Mountains, creates other snow travel hazards and challenges, in the spring and early summer. You can monitor the snowpack along the Pacific Northwest Trail, here.

Two sections of the PNT — the Wilderness Coast, Section 10 and the Puget Sound, Section 8 — are located in more temperate climates and have much longer seasons. These popular sections of trail can be visited May through October, with heavy rains, and more frequent storms, occurring in winter.

During winter, high levels of precipitation falls on the Olympics and Cascades with heavy rains at lower elevations and large amounts of snowfall at higher elevations.

Heavy snow and rain, at high elevations, characterize the North Cascades and Olympic Mountains every winter. Avalanches are common in winter and spring in these steep mountains. Other early season hazards include snow bridges, river fords, high-angle snow travel, “elephant traps,” and other snow travel hazards.

Special equipment and knowledge can greatly minimize the risk posed by these hidden hazards, but does not eliminate the serious risks they pose to one’s personal safety. Low angle snow on hiking trails can make progress difficult and slow. Snow can also obscure hazards, like snags, and make navigation more difficult.

Helpful Links:

Learn more about snow and snow travel on the PNT, here.

The Northwest Avalanche Center provides detailed forecasts for the Olympic Mountains and North Cascades.

The Idaho Panhandle Avalanche Center provides avalanche forecasts for the Selkirk Mountains and the Purcell Mountains.

The Flathead Avalanche Center provides avalanche forecasts for the Rocky Mountains and the Whitefish Range.

Milder summer temperatures in the Pacific Northwest typically change to cooler, wetter weather at lower elevations in late September.

In the Northwest, the transition from mild weather in summer, to severe winter weather in fall, can happen very suddenly. Early fall storms can bring feet of snow, or cold heavy rain, which make backcountry conditions more difficult. This time of year, enough snow and ice can accumulate in a single storm to make steep trails very dangerous, even impassable.

Late season visitors should be aware that Glacier National Park typically begins to remove seasonal bridges and close trails in late September.

Resources

The Natural Resources Conservation Center provides an interactive map to monitor the snowpack in the western states.

The Northwest Avalanche Center provides detailed forecasts for the Olympic Mountains and North Cascades.

The Idaho Panhandle Avalanche Center provides avalanche forecasts for the Selkirk Mountains and the Purcell Mountains.

The Flathead Avalanche Center provides avalanche forecasts for the Rocky Mountains and the Whitefish Range.