If you’re planning your first Alaska cruise, the weather (and cold) is probably one of your biggest concerns. Luckily, the weather is milder than you think. Summer temperatures along the Inside Passage range from 55°F to 65°F between May and September. You won’t need a parka, but you will need a rain jacket.
Rain, not cold, is the real weather story on an Alaska cruise. It can roll in fast, sometimes within minutes of a clear sky, and it gets heavier as the season goes on.
Every month from May through September brings a different mix of temperatures, rainfall, daylight, and crowds. May is cool and dry. July is warm and busy. September is wet but affordable.
Below, you’ll find a month-by-month breakdown of Alaska cruise weather, how conditions change at each port, and what the forecast means for shore excursions and packing. For help choosing the right month, see our best time to cruise Alaska guide.
Alaska Cruise Weather at a Glance
The table below shows average weather conditions along the Inside Passage, based primarily on Juneau-area climate data. Keep in mind that conditions vary by port. Ketchikan is much wetter, and Skagway is much drier. We cover those differences further down.
Month | Avg Low | Avg High | Avg Rainfall | Daylight Hours | Crowd Level |
|---|---|---|---|---|---|
May | 40°F | 58°F | 3.51″ | 16.5 hrs | Low |
June | 47°F | 62°F | 3.82″ | 18 hrs | High |
July | 50°F | 64°F | 5.14″ | 17.3 hrs | Peak |
August | 49°F | 63°F | 6.41″ | 15.2 hrs | High |
September | 44°F | 56°F | 9.15″ | 12.4 hrs | Low |
Data reflects NOAA 1991-2020 climate normals for Juneau, AK. Actual conditions vary by port and day.
Not sure which month to pick? Here’s the quick version:
Best weather: Late June through mid-July. These months have the warmest days, the longest daylight, and the most comfortable conditions for outdoor excursions.
Least rain: May and early June. If dry weather matters more than warm weather, these months have the lowest average rainfall.
Best value: Early May or September. Fewer ships, cooler weather, and kids back in school mean lower fares and smaller crowds at every port.
Best wildlife: July and August. Salmon runs pull bears to the rivers, and humpback whales are active all season long. You can never guarantee wildlife sightings, but these months provide the best opportunities.
Northern Lights: September has the longest nights, providing the best opportunity to see the aurora borealis.
Month-by-Month Guide
Those averages tell part of the story. But each month has its own personality, and the weather shapes everything from which excursions are worth booking to what you and your kids should wear off the ship.
Here’s what to expect.
Alaska Cruise Weather in May
May is the quiet start to the Alaska cruise season. Highs average around 58°F, with lows near 40°F. Rainfall is the lowest of any cruise month at 3.51 inches (89mm), and you get about 16.5 hours of daylight.
That combination of cool, dry weather and long days makes May one of the most underrated months to cruise Alaska. The ports aren’t crowded yet. Fares are lower than peak summer. And the mountains still have heavy snow cover, which makes the scenery sharper and more dramatic than it looks later in the season.
Wildlife is active, too. Humpback whales are finishing their migration north, so while not peak season, you can catch glimpses of whales. On shore, spring means newborn bear cubs, moose calves, and seal pups. You won’t see the salmon-fueled bear feeding frenzy of midsummer, but quieter wildlife encounters have their own appeal.
The trade-off is temperature.
Mornings and evenings feel cold, especially on deck. If your family is planning outdoor excursions like glacier hikes or kayaking, everyone needs warm layers. Kids especially. A fleece mid-layer and a windproof shell make a big difference when you’re standing on a boat watching glaciers calve.
One more perk, fewer mosquitoes, which makes hiking trails much more pleasant to navigate.
For a deeper look at how May compares to other months, see our best time to cruise Alaska guide.
Alaska Cruise Weather in June
June is when the Alaska cruise season begins to hit its stride. Highs reach about 62°F, lows settle around 47°F, and rainfall stays moderate at 3.82 inches (97mm).
The big draw is daylight. Around the summer solstice, Juneau gets roughly 18 hours of sunlight. The sun barely dips below the horizon. Even in the middle of the night, it doesn’t truly get dark. It was a bit of an odd sensation when I first experienced an Alaskan summer night. If you’re a light sleeper, you’ll want to book an interior cabin, which is much darker.
All that light changes the feel of a cruise day.
You have more time for shore excursions without rushing. Kids can stay on deck watching for wildlife well into the evening. And the warm temperatures make outdoor activities like hiking, kayaking, and fishing comfortable for the whole family.
June is also one of the better months for glacier viewing. Warmer air accelerates ice movement, which means more frequent calving events. If watching a wall of ice crack and crash into the sea is on your list, June delivers.
Wildlife picks up across the Inner Passage and Tongass National Rainforest. Black bears and brown bears are foraging along shorelines, and whale watching stays strong through the month.
A few things to plan for.
Mosquitoes increase in June, especially near fresh water and on forest trails. Pack insect repellent for any hiking excursion. And while rainfall remains relatively low, June weather can shift quickly. A sunny morning doesn’t guarantee a sunny afternoon. Keep a lightweight rain jacket in your daypack.
Mosquitoes are mostly an issue on wooded shore excursions or near standing water, not on the ship itself. It’s very unlikely you’ll encounter any mosquitoes on the ship. And I don’t find them to be a problem walking around most towns.
Fares climb through June as demand increases. If budget matters, early June offers slightly better pricing than the back half of the month.
Alaska Cruise Weather in July
July is the warmest month of the Alaska cruise season, and it’s also the busiest. Highs average 64°F with lows around 50°F. Rainfall increases to 5.14 inches, and you still get over 17 hours of daylight.
Here’s the thing about July: the averages look great, but the weather is unpredictable. You can start a morning in Juneau under blue skies and be standing in cold rain two hours later. That’s not unusual. It’s just how the weather works along the Inside Passage.
To enjoy your July cruise in Alaska, layer up and roll with the ever-changing weather.
The warmth and long days make July the best month for active excursions. Glacier hikes, zip-lining, fishing charters, and whale watching all benefit from the conditions. If you have kids who want to be outside and moving, this is the month.
Don’t skip the sunscreen.
At Alaska’s latitude, UV exposure on clear days is stronger than most first-time visitors expect. Sunglasses are worth packing for everyone.
Wildlife is a highlight. Salmon runs begin towards the end of July, pulling brown bears and black bears to rivers and streams across Southeast Alaska. Bear viewing excursions out of Juneau and Ketchikan are at their best. And humpback whale activity stays strong.
The downside is crowds and cost. July is peak season. Ships are full. Ports are busy. Fares are at their highest. And popular shore excursions sell out weeks in advance. If July is your month, book early.
Alaska Cruise Weather in August
August is when the Alaska cruise season starts to turn. Highs average 63°F and lows around 49°F, so temperatures stay close to July levels. But rainfall jumps to 6.41 inches. That’s a noticeable increase. Expect rain on more days than not, especially in Ketchikan and Juneau.
Don’t let that discourage you.
August rain tends to come in short waves rather than all-day downpours. You’ll get wet stretches of rain followed by breaks. And the scenery actually benefits from it. Fall color starts creeping across the mountainsides, and overcast skies give glaciers a moody, dramatic look that photographs beautifully.
This is prime time for wildlife. Salmon runs are in full swing, and bears are feeding aggressively before winter. August is arguably the best month for bear viewing along the Inside Passage. Humpback whales remain active. If seeing bears catch salmon is high on your family’s list, August is your month.
For families with school-age kids, August is often the most practical choice. You’re still inside the summer break window, and fares start to decrease in the second half of the month. You won’t find September-level deals, but late August pricing beats July.
Packing matters more in August than in any other month. Waterproof hiking shoes, wool socks, and a quality rain jacket should be in every family member’s bag. Cotton layers that soak through and stay cold are the fastest way to end an excursion early.
For a complete gear list, check out our Alaska cruise packing guide.
Daylight drops to about 15.2 hours. Still plenty of time for a full day of excursions, but you’ll notice the difference if you cruised earlier in the summer.
Alaska Cruise Weather in September
September is the shoulder season, and it feels like it. Highs drop to 56°F, lows settle near 44°F, and rainfall peaks at 9.15 inches. That makes September the wettest and coolest month of the cruise season. Daylight shrinks to about 12.4 hours.
Sounds awful. So why do people love it?
Price, for one. September fares are well below peak summer rates. The shoulder season has gotten more popular in recent years, so the deep last-minute deals aren’t as common as they once were. But you’ll still pay significantly less than a July sailing.
Crowds thin out as kids return to school, and families can’t travel. The cruise ports feel calmer, and shore excursion groups are smaller.
If you’ve ever stood in a line of 200 people waiting to get off a ship in Juneau, you’ll appreciate the difference.
And then there’s the Northern Lights. September is the only cruise-season month with short enough nights to give you a realistic chance at seeing the Aurora Borealis from the ship. No guarantees, but longer nights with the sun dipping deeper beyond the horizon give you a better chance of seeing atmospheric activity.
The landscape shifts, too. Fall colors spread across the mountains and forests. The greens of summer start giving way to golds and reds. It’s a different Alaska than what you’ll see in July, and many repeat cruisers say it’s their favorite.
Wildlife is still around. Bears continue feeding before hibernation. Salmon runs are winding down, but are still active in some areas. Whale sightings are possible but less common than in midsummer.
Prices are lower, and there’s fewer crowds but rain is frequent and sometimes heavy.
Plan for wet weather on most days. Your family needs waterproof gear from head to toe. Shorter days also mean earlier sunsets, which limits on-deck wildlife watching in the evenings. But for families with flexible schedules, especially homeschooling families or those with younger kids not yet in school, September offers the best combination of value, atmosphere, and elbow room.
How Weather Varies by Port
One thing most Alaska cruise weather guides skip: the Inside Passage isn’t one weather zone. It stretches roughly 500 miles from Ketchikan in the south to Skagway in the north, and many itineraries extend into the Gulf of Alaska through Seward and Anchorage.
Weather conditions change at each stop. The weather you experience on Monday in Ketchikan can feel nothing like the weather on Wednesday in Skagway.
Here’s what you can expect in some of the popular cruise ports:
Ketchikan is the wettest major port on the route, averaging around 141 inches of rain per year. To put that in perspective, Seattle gets about 37 inches. Rain here is not a possibility. It’s a near-certainty. Some locals joke that if you can’t see the mountains, it’s raining, and if you can see the mountains, it’s about to rain. Waterproof everything for your Ketchikan excursion. Bring waterproof shoes, a lightweight rain jacket, and water-resistant pants if you have them. You’ll enjoy the port a lot more if you’re dry.
Juneau gets less rain than Ketchikan at around 67 inches per year, but it makes up for it with clouds. Juneau ranks among the cloudiest cities in the United States, with overcast skies on roughly 280 days per year. Rain is possible on any given day, but it’s usually lighter and shorter than in Ketchikan. You might get a few hours of sun between the gray stretches.
Skagway is the pleasant surprise. It sits in a rain shadow created by the surrounding mountains, and annual rainfall drops to about 25 inches. That’s roughly a third of what Juneau sees. If your cruise includes Skagway, this is the port day most likely to greet you with blue sky. Plan your most weather-dependent excursion here if your itinerary allows it.
Seward is a common embarkation or disembarkation port for one-way Gulf of Alaska cruises. It sits on Resurrection Bay along the southern Kenai Peninsula, exposed to moisture coming off the Gulf. That means rain. Seward averages around 64 inches of precipitation per year, and summer temperatures run cooler than the Inside Passage, with July highs around 57°F. If your cruise starts or ends here, expect conditions that feel more like early-season Inside Passage weather, even in midsummer. Pack warmer clothes to account for the more northern climate.
Anchorage surprises most people. It’s much drier than the coastal ports, averaging only about 16 inches of rain per year. Summer highs reach the mid-60s in July, sometimes warmer. If your itinerary includes a pre- or post-cruise stay in Anchorage, you may get the sunniest, driest weather of the whole trip. Don’t assume it will feel like the rest of your cruise. Despite the cold, you might actually need the sunscreen here.
Glacier days at sea are a different story. When your ship is near Glacier Bay or Hubbard Glacier, expect colder and windier conditions than anything you felt in port. Wind chill on the upper decks can make it feel 10 to 15 degrees colder than the posted temperature. A warm hat, gloves, and a wind-blocking outer layer are worth having on hand for glacier viewing. The scenery is worth standing outside for, but not if you’re shivering too hard to enjoy it.
A good rule of thumb: pack for Ketchikan, and you’ll be prepared for every port on the route.
Alaska Cruise Weather FAQ
What is the best month to cruise Alaska for good weather?
Late June through mid-July offers the best combination of warm temperatures, long daylight, and manageable rainfall. July is the warmest month, with average highs around 64°F in Juneau. That said, “best” depends on your priorities. May and early June are drier, but coolerr. September is cheaper and less crowded, but it is the rainiest month in the cruise season. For a full comparison, see our best time to cruise Alaska guide.
How cold does it get on an Alaska cruise in summer?
Not as cold as most people expect. Summer lows along the Inside Passage range from about 40°F in May and September to 50°F in July. You won’t need heavy winter gear. The exception is glacier viewing days, when wind chill on the upper decks can make it feel 10 to 15 degrees colder than the air temperature. Warm layers, a windproof jacket, and a hat handle it.
Does it rain a lot on Alaska cruises?
Yes, rain is part of the experience. May and June are the driest months, with roughly 3.5 inches per month. Rainfall increases through the summer, reaching 6.4 inches in August and 9.15 inches in September. Rain is heaviest in Ketchikan, which gets around 141 inches per year. Waterproof shoes and a rain jacket are essential, no matter which month you sail.
Is it always cloudy in Alaska?
Overcast skies are common, especially in Juneau, which is one of the cloudiest cities in the United States. But “cloudy” doesn’t mean “dark.” Summer daylight is abundant, and the clouds often lift and shift throughout the day. Many cruisers find that overcast conditions actually make for better glacier and wildlife photos, with softer light and fewer harsh shadows.
Can you see the Northern Lights on an Alaska cruise?
Yes, but there’s no guarantee. September is your best bet to spot the aurora borealis. The summer months have too much daylight for the Aurora to be visible. By September, daylight drops to about 12.4 hours, and clear nights away from port lights can offer viewing opportunities. It’s not guaranteed, but September is your only realistic chance during the cruise season.
Is the weather different at each port?
Yes, very much. Ketchikan averages 141 inches of rain per year. Juneau gets about 67 inches. Skagway sees only 25 inches, thanks to a rain shadow from the surrounding mountains. If your cruise reaches Anchorage, you’ll find it surprisingly dry at just 16 inches per year. Weather can shift significantly from one port stop to the next, so pack layers and rain gear for the wettest port, and you’ll be ready for all of them.
What should I wear on Alaska cruise shore excursions?
Layer for changing conditions. A moisture-wicking base layer, a fleece mid-layer, and a waterproof shell jacket cover most situations. Waterproof hiking shoes handle wet trails and dock areas much better than sneakers or sandals. Avoid cotton, which stays cold and damp when wet. Even on a sunny morning, carry a compact rain jacket in your daypack. For a complete gear list, see our Alaska cruise packing guide.
Will my kids be comfortable on an Alaska cruise?
Kids do well on Alaska cruises as long as they’re dressed for the weather. I loved my first Alaskan cruise when I was 12 years old.
Kids need the same layering system as adults: base layer, fleece, waterproof shell. Pack extra dry socks and a spare set of warm layers, because wet, cold children end excursions early. Binoculars keep kids engaged during wildlife watching. July and August are the most popular months for families, with the warmest temperatures and the most kid-friendly excursion options available.
References
- NOAA National Centers for Environmental Information. “U.S. Climate Normals 1991-2020.” Accessed May 2026. https://www.ncei.noaa.gov/products/land-based-station/us-climate-normals
- US Climate Data. “Climate Juneau – Alaska.” Based on NOAA 1991-2020 normals. Accessed May 2026. https://www.usclimatedata.com/climate/juneau/alaska/united-states/usak0116
- National Weather Service, Juneau Forecast Office. “Juneau and Area Climate Information.” Accessed May 2026. https://www.weather.gov/ajk/localclimate
