Glacier Bay Weather: Forecasts, Climate, and Current Conditions

By Erika Müller · Data: National Park Service · ← Complete guide Glacier Bay

Glacier Bay has a temperate rainforest climate. Rain is the norm year-round, temperatures stay cool even in July, and the park's glaciers show themselves under any kind of sky. In summer, daytime temperatures range from 50 to 63°F. April, May, and June are the driest months; September and October are the wettest. In short, aim for spring or early summer if you want the best chance of sunshine. For wildlife and solitude, fall makes up for the rain with low-angle light on the icebergs.

Glacier Bay's Climate Month by Month

The averages below come from Bartlett Cove, the park headquarters 10 miles from Gustavus. Use them as a baseline when choosing your gear and planning your activities.

The main takeaway is that the annual temperature range stays narrow because the Pacific's maritime influence moderates the climate. Annual precipitation tops 47 inches. That's exactly what feeds the park's more than 1,000 glaciers.

The Climate Season by Season

Winter (November to March)

Winter in Glacier Bay isn't polar in the Arctic sense, but it's wet, dark, and unforgiving for visitors who aren't prepared. Temperatures regularly fall below freezing at night, and snow may stick around for several days at Bartlett Cove. Visitor services are suspended. Glacier Bay Lodge closes, flights from Juneau become less frequent, and no cruise ships travel through the bay. The park remains technically accessible without an entrance gate, but you'll need complete logistical self-sufficiency. A few rangers wintering over, some wolves, and you.

Spring (April to June)

April, May, and June offer the year's best weather compromise. Rainfall is much lower than in fall, daylight rapidly increases to 18 hours in June, and wildlife becomes active again. Humpback whales return to the bay as early as May. Snow remains at higher elevations, creating a striking contrast between the glaciers and the greenery returning below. The sea is still cold, at 41 to 46°F, so kayaking requires a dry suit.

Summer (July to August)

July is the peak month. It's the warmest, sunniest, and busiest time of year. Some afternoons on the Bartlett Cove terrace can approach 68°F. Cruise ships fill the bay, and the visitor center runs at full capacity. During our sea-kayaking trip in July, we had three days of brilliant sunshine, one day of mist, and one day of steady rain. That's roughly the ratio to expect. August is still an excellent month, but rainfall rises sharply and the days get shorter quickly.

Fall (September to October)

September and October bring the heaviest rainfall. Cruises stop, visitor numbers plummet, but moose and brown bears are more visible along the forest edge. Late-day light on the ice is spectacular. Conditions on the water deteriorate, however. Winds strengthen, and calm windows for kayaking get shorter. This season suits self-reliant hikers and travelers content with boat excursions from Bartlett Cove.

Is Glacier Bay Cold?

Yes, and it's especially damp. The temperatures themselves aren't extreme because the ocean moderates them, but the wind chill feels sharper than expected as soon as wind picks up over the water. In winter, bursts of continental cold can push temperatures down to 14°F or lower. In summer, the warmest days approach 68°F, but those spells are brief exceptions. Glacier Bay's real climate challenge isn't freezing temperatures. It's the combination of rain, wind, and humidity, which can overwhelm average gear in a few hours. Our complete Glacier Bay guide breaks down conditions by activity to help you prepare.

What to Wear and Pack by Season

The golden rule in Glacier Bay is simple: layer up and stay fully waterproof, whatever the morning forecast says.

Year-round essentials:

• Waterproof, breathable jacket (Gore-Tex or equivalent). A light windbreaker isn't enough
• Fleece or merino wool midlayer
• Gloves and a hat, even on the water in July
• Waterproof shoes with grippy soles (the trails around Bartlett Cove are often soaked)

Winter and shoulder seasons:

• Waterproof pants
• Insulated boots
• An extra thermal layer for your lower body

For sea kayaking:

• Dry suit required (water temperatures stay between 41 and 50°F year-round, and capsizing can cause hypothermia quickly)
• Coast Guard-approved personal flotation device, worn at all times
• Marine VHF radio or SPOT device, essential in the bay because there's no cell coverage

Always pack a dry change of clothes in a dry bag. Ambient moisture can saturate mid-range gear in a single day.

Weather Alerts and Conditions to Watch

Glacier Bay has several specific hazards that standard weather reports don't capture.

Katabatic winds. Glaciers generate sudden blasts of cold descending air, especially in the West Arm (Tarr Inlet). In a kayak, a stable window can turn into a localized storm in less than an hour, with no advance warning.

Glacier calving. When a wall of ice falls into the water, it creates waves that can destabilize a kayak hundreds of yards away. NPS rules require a minimum distance of 1,300 feet from the face of active glaciers. This isn't a suggestion; it's a regulation.

Air access. The connection from Juneau, the only scheduled transportation, can be interrupted for several consecutive days by fog or low ceilings. Build a buffer day into your itinerary if you have a connection to make. The park's only road from Gustavus to Bartlett Cove, 10 miles long, can also be blocked by downed trees or flooding in fall. For real-time alerts and current closures, check the park's official website at nps.gov/glba.

Frequently Asked Questions