A Month-by-Month Guide to Weather on a Southeast Alaska Cruise
- Brian Gibbons
- Mar 29
- 3 min read
Cruising through Southeast Alaska—home to stunning fjords, glaciers, and coastal towns like Juneau, Ketchikan, and Skagway—is a bucket-list adventure. The weather in this region, shaped by its temperate rainforest climate, varies significantly throughout the cruise season (typically May to September). Below, I’ve broken down what you can expect month by month, focusing on the likelihood of rain, sunny skies, and warm temperatures. Whether you’re planning a trip or just curious, this guide will help you set your expectations.
May: A Cool and Showery Start
Temperatures: Average highs range from 50°F to 55°F (10°C to 13°C), with lows dipping into the 40s°F (4°C to 7°C).
Rain: May kicks off the cruise season with a decent chance of rain—expect precipitation on about 15-17 days of the month. Showers are often light but frequent.
Sunny Skies: Clear days are less common, though you might get 5-7 days of partial sunshine. Cloud cover dominates as spring transitions to summer.
Vibe: It’s chilly and damp, but the landscapes are lush, and snow-capped peaks still gleam. Pack layers and waterproof gear.
June: Longer Days, Milder Weather
Temperatures: Highs climb to 55°F to 62°F (13°C to 17°C), with lows in the upper 40s°F (8°C to 10°C).
Rain: Rain remains a regular guest, falling on 14-16 days. However, showers are often brief, leaving room for drier spells.
Sunny Skies: June offers the best shot at sunshine, with 6-8 clear or partly sunny days, thanks to the longest daylight hours (up to 18 hours near the solstice!).
Vibe: Warmer and brighter, June feels like the sweet spot for many cruisers. Flowers bloom, and wildlife is active—perfect for scenic deck time.
July: Peak Warmth, Peak Rain
Temperatures: The warmest month, with highs between 60°F and 65°F (15°C to 18°C) and lows around 50°F (10°C).
Rain: July is also the wettest, with rain on 17-20 days. Expect a mix of drizzles and steadier downpours, especially in the afternoons.
Sunny Skies: Sunshine takes a backseat, with only 4-6 clear days. Partial sun is more common, but clouds often rule.
Vibe: It’s as warm as Southeast Alaska gets, ideal for outdoor excursions, though you’ll need rain gear handy. The lush greenery is at its peak.
August: A Wetter, Cooling Transition
Temperatures: Highs drop slightly to 58°F to 63°F (14°C to 17°C), with lows in the upper 40s°F to low 50s°F (9°C to 11°C).
Rain: Rainfall ramps up, hitting 18-20 days. August often feels soggier than July, with heavier showers possible.
Sunny Skies: Clear days dwindle to 3-5, though you’ll still get some breaks in the clouds for glacier views.
Vibe: The air hints at autumn, and the rainforest thrives in its damp glory. It’s a moody, misty time—great for photography if you don’t mind the wet.
September: Crisp, Quiet, and Rain-Soaked
Temperatures: Highs fall to 50°F to 57°F (10°C to 14°C), with lows in the 40s°F (4°C to 7°C).
Rain: The wettest month of the cruise season, with rain on 20-22 days. Expect steady, soaking showers rather than fleeting drizzles.
Sunny Skies: Sunshine is rare—maybe 2-4 clear days. Fog and overcast skies dominate as fall settles in.
Vibe: Cooler and quieter, September offers fewer crowds and vibrant fall colors, but it’s the least forgiving weather-wise. Waterproof everything is a must.
Final Tips for Your Alaska Cruise
Southeast Alaska’s weather is famously unpredictable, so these are averages based on historical patterns. Rain is a near-constant companion (it’s a rainforest, after all!), with 50-70 inches falling during the May-to-September season. Sunny skies are a treat, not a guarantee, and “warm” is relative—60°F feels balmy here. Pack a waterproof jacket, sturdy shoes, and a flexible attitude. The weather might shape your trip, but the rugged beauty of glaciers, whales, and misty mountains shines through regardless.
Which month sounds like your ideal cruise time? Let me know if you’d like more details!
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