Glacier National Park Weather: What to Expect in the Montana Rockies

As an Amazon Associate, I earn from qualifying purchases. We may receive a commission for purchases made through these links. This site also contains affiliate links to products besides Amazon and we may also receive a commission for purchases.

Glacier National Park is full of natural beauty. We absolutely loved visiting, and we got to experience some of the best hikes while we were there. But, planning a trip to Glacier can be difficult because of the unpredictable weather. Never fear!

We’ve experienced it, and we’re ready to spill the beans on the Glacier National Park weather drama.

In this guide, we’ll navigate the nuances of this natural wonder, preparing you for the best trip possible against the backdrop of towering peaks and pristine valleys.

We were lucky enough to visit in mid-September and had absolutely fantastic weather for the season. We were also able to talk to area locals and park staff, who let us in on a few great secrets about when to visit.

From unpredictable rain showers to the crisp chill of mountain air, Glacier National Park’s weather is a character in its own right, adding an extra element of difficulty in planning your trip, but we have you covered.

Pack your rain gear, your extra layer, and your shorts. During the busy season, you just might need all of these during your trip.

Sam observes ice still floating in the lake next to Grinnell Glacier on a sunny day in September. — Even on a sunny September day, there was still ice floating in the lake next to Grinnell Glacier.

What is the Weather Like in Glacier National Park?

Nestled in the Rocky Mountains of northern Montana, Glacier National Park has weather conditions as diverse and quickly changing as the landscape. From the peaks high up on Going to the Sun Road to the meadows and valleys below, each corner of the park can feel different.

Glacier National Park experiences pronounced weather extremes, featuring very snowy winters and brief but beautiful summer seasons.

Winter transforms the park into a snow-laden wonderland, perfect for snowshoeing and cross-country skiing.

Spring weather is still chilly. However, as the season progresses, there are more opportunities to explore the park. Hop on a bike and explore Going-to-the-Sun Road to its closure point or hike at lower elevations.

Summers, though short, typically offer pleasant temperatures and a burst of colorful wildflowers in the middle.

Fall is a beautiful time to visit, but the grizzly bears are preparing for hibernation, so they’re hungry and active. While this isn’t a weather concern, there are often trail and campsite closures due to bear activity.

The main road, Going-to-the-Sun Road, typically opens for just a few months each year, from July to September (October at the latest), limiting the window for visitors to traverse its iconic route.

Best Time to Visit Glacier National Park

Timing is everything when it comes to being able to experience Glacier. While the park welcomes visitors throughout the year, the ideal time to access the full spectrum of its natural beauty is during the summer months, from July to September.

During this period, temperatures are generally milder, and most of the park’s amenities are open and accessible.

The opening of Going-to-the-Sun Road varies each year, depending on the amount of snowfall and temperatures early in the season.

From July to September, though, the length of the road is typically accessible for driving, bridges have been placed by trail crews, and snowpack disappears along the trails at higher elevations.

These are the best times to visit Glacier National Park, depending on what you’re looking for:

Wildflower Blooms: Late July
Snowcapped Peaks: June
Full Access to Going to the Sun Road: July through September

August is also a great time to take a Red Bus Tour in Glacier. You’ll have the best chance at warmer weather, so the top can be left open in the red bus. You can get some of the best views along Going-to-the-Sun Road without having to drive it yourself!

You can pick up a Red Bus Tour from multiple points in the park, both on the west and east sides.

How to Prepare for the Conditions in Glacier

Before embarking on your Glacier National Park adventure, it’s crucial to prepare for the dynamic weather conditions you might encounter. Here’s a checklist to ensure you’re ready for whatever Mother Nature throws your way:

1. Have a Raincoat Close By

Glacier National Park is no stranger to sudden rain showers. The weather changes quickly in the mountains, and it isn’t easy to get a weather forecast based on location.

Be prepared with a reliable raincoat to stay dry and comfortable during your outdoor escapades.

You don’t want to get a few miles out on a hiking trail and have a heavy rain shower pop up without a jacket. That makes for a miserable (and potentially dangerous!) remainder of your hike.

2. Prepare for Chilly Conditions at Higher Elevations

Higher elevation brings cooler temperatures and often windier conditions.

Don’t let a warm valley fool you. Both East and West Glacier are much lower and typically warmer than up at Logan Pass.

Sometimes, the difference can be 20 degrees F!

When exploring mountainous terrain, pack layers to stay warm as you ascend to those chilly summits. If you begin your hikes earlier in the morning, wear layers that you can shed as the temperatures heat up throughout the day.

3. Remember Your Sun Protection

At higher elevations, the sun’s rays are more intense.

There aren’t any trees to hide under when you’re hiking above the treeline. Many of the best trails, like Grinnell Glacier and the Highline, have very little shade for much of the route.

Arm yourself with sunscreen, sunglasses, and a wide-brimmed hat to shield yourself from the Montana sun.

We even stopped to reapply sunscreen while hiking to Sperry Chalet. As a result of a 2017 fire, much of the trail is still open.

I’m also a big fan of a breathable, hooded long-sleeve shirt for these conditions, keeping the sun off of my neck and arms. The hood is also helpful for any wind at higher elevations or on ridgelines! I was really happy to have one on while hiking Siyeh Pass.

4. Bring Plenty of Water

Staying hydrated is key, especially in this alpine environment.

Carry a reusable water bottle and refill it regularly at the park’s designated water stations.

Having a water filter in your pack can also be helpful, especially for longer hikes. Refill at a stream crossing or the backcountry lake you pass on your hike.

We love our Katadyn Hiker Microfilter and always have it in our pack when out and about. It makes filling both bottles and water bladders really easy in a pinch.

5. Layers are No Joke (You’ll Need Them!)

Both Montana and mountain weather can change in a heartbeat.

Dressing in layers allows you to adapt to shifting conditions and ensure you are as comfortable as possible.

You’ll want to shed layers in the warm midday sun, but you’ll be happy to have a jacket on chilly mornings.

I was happy to have layers that included a short sleeve, a long sleeve, and a windbreaker. Hats and gloves can be helpful for chilly mornings, especially at higher elevations. You can be comfortable in shorts, though, on warm summer afternoons!

A light dusting of snow covers a Montana mountain road surrounded by trees also covered with snow. Narrow tire tracks travel around the curve. Glacier National Park weather is unpredictable and it is possible there can be snow any month of the year. — There is plenty of snow in Glacier during the winter, making many things inaccessible. A light dusting covers the road here, but Going-to-the-Sun Road is typically buried by many feet of snow.

Montana Elements to be Aware Of

While some of these are typical of many mountainous locations, it’s still good to review and be prepared!

Brace yourself for a possible weather rollercoaster, swinging from chilly mountain nights to sunny valley days.

Stay savvy about fire conditions, play it safe when conditions appear potentially unfavorable, and respect the park rules to navigate this beautiful landscape like a pro.

Low Temperatures

Even in the summer, Glacier National Park can experience chilly nights, particularly at higher elevations.

Pack a warm jacket and consider thermal layers to stay cozy during cooler evenings. We love our merino wool baselayers and were really happy to have them for the chilly nights dipping down into the 30s sleeping in our tent.

Even in July, nighttime temperatures can dip down into the 40s, while daytime sun can bring days in the 80s.

Wind

Even if it’s calm in the gateway town before you head up Going to the Sun Road, that doesn’t necessarily mean that you’re in for a calm day!

Winds at the top can be quite gusty! You’ll want to have a jacket with you to break the wind.

Even outside the coldest month in Glacier, the strong winds can chill you right to the bone.

Precipitation

Rain or snow can surprise visitors at any time of the year.

While it isn’t common, it can certainly snow any month of the year. Yes, even in July and August.

Be prepared with waterproof rain gear to keep dry in case the skies decide to open up.

It isn’t necessary to invest a ton of money into full rain gear, but having some basic rain pants and a good weatherproof jacket can be a lifesaver in a downpour. We luckily didn’t run into any downpours in Glacier, but we have been happy to have our rain gear in other places and always make sure to pack it.

Fires

While Glacier National Park is a haven for natural beauty, it’s also very susceptible to wildfires. Smoke from wildfires farther west in Oregon, Washington, and northern California can also affect the skies in Glacier, too.

Typically, fire season is the worst during the month of August. Smoke conditions can change from day to day, but can sometimes affect visibility and air quality.

Stay informed about fire conditions, adhere to park regulations, and exercise caution to ensure a safe and enjoyable visit.

You can check current fire conditions, including the location, size, and percentage of containment through the National Wildfire Coordinating Group incident system here.

A landscape along the Siyeh Pass Trail through the Sunrift Gorge still has evidence of the Reynolds Creek Fire, which burned through the area in 2015.

Just Be Prepared for Glacier National Park Weather!

Preparing for the weather in Glacier National Park is a vital step in trip planning.

Check current weather conditions, reported from the airport in Kalispell, here if your trip is coming up very soon!

With the right gear and an awareness of Montana’s dynamic elements, you’ll be ready for a Glacier adventure that will leave you in awe. It’s one of the most beautiful national parks in the US.