Glacier's summer weather is as varied as its landscape. The western valleys generally receive the most rainfall, but daytime temperatures can exceed 90 F. It is frequently 10 to 15 degrees cooler at higher elevations. Sunny days often predominate on the east side of the park; however, strong winds frequently occur. Overnight lows in the park can drop to near 20 F, and snow can fall anytime.
Prepare for a variety of conditions and pack accordingly. You may start in a T-shirt and shorts, and need a parka by evening. Dress in layers. Always bring raingear.
The data chart shown here was collected over the last ten years at Park Headquarters in West Glacier, at an elevation of 3,200 ft. Temperatures and rainfall amounts are often much different in other parts of the park.