What to Pack for a Cruise to Alaska in August: July’s Warmth, Heavier Rain

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An August afternoon in Ketchikan is normally 64.7°F. In July it’s 64.5°F. So you can pack the same suitcase as a July cruiser, right?

Not quite. Ketchikan’s normal rainfall jumps from 7.33 inches in July to 11.30 in August, and it rains on barely more days. August in Alaska isn’t colder. It’s the same summer with the tap turned up.

What to Pack for a Cruise to Alaska in August

Pack summer clothes and serious rain gear: short and long sleeves, light pants, a fleece, a properly waterproof hooded jacket, rain pants and two pairs of waterproof shoes. Average port highs run from 60°F to 65°F, with lows around 48°F to 53°F. Add binoculars, polarized sunglasses, sunscreen and one small bottle of insect repellent. You can leave the parka at home.

Is August Really Wetter Than July in Alaska?

Yes, at every port we checked. We downloaded the official 1991–2020 monthly normals for six cruise stops from NOAA’s National Centers for Environmental Information, then worked out one thing the raw tables don’t show: how much rain falls on an average wet day. The Juneau and Ketchikan figures match the NOAA tables on Wikipedia’s Juneau and Ketchikan pages.

Port	August high / low	July high	Rain, July → August	Wet days, July → August	Rain per wet day, July → August
Ketchikan	64.7°F / 53.3°F	64.5°F	7.33 → 11.30 in	16.0 → 16.8	0.46 → 0.67 in
Sitka	61.8°F / 52.9°F	60.4°F	4.62 → 7.25 in	18.9 → 19.4	0.24 → 0.37 in
Juneau	62.9°F / 49.1°F	64.0°F	5.14 → 6.41 in	18.5 → 19.4	0.28 → 0.33 in
Glacier Bay (park station)	60.0°F / 47.9°F	60.7°F	4.76 → 5.97 in	not published	not available
Skagway	63.4°F / 51.0°F	64.5°F	1.38 → 2.35 in	11.0 → 14.6	0.13 → 0.16 in
Seward	62.0°F / 49.6°F	62.2°F	3.11 → 5.39 in	13.4 → 15.2	0.23 → 0.35 in

• The temperature barely moves. Every August high is within 1.4°F of July’s. Ketchikan and Sitka are actually warmer in August.
• The rain does move. Monthly totals rise by 25% in Juneau and Glacier Bay, 54% in Ketchikan and 73% in Seward.
• It’s heavier, not just more frequent. Ketchikan gets less than one extra wet day, but about 0.2 inch more on each one. That’s a wetter day, not just a wetter month, and it’s why we wouldn’t rely on a thin poncho.
• Skagway is your best bet for a dry day, with the least rain and the fewest wet days of the five stations that count them.

Cruise lines describe August differently, so here’s how their claims compare. Royal Caribbean calls August “the wettest month of Alaska’s cruise season.” NOAA’s normals show September wetter at all six stations, as our September guide found. Princess says that in August “temperatures start to drop.” Highs do slip at four of the six stations, by about a degree at most. The real drop comes in September, when highs fall 4°F to 7°F. Celebrity says Juneau averages 17 wet days in August, while NOAA’s figure is 19.4.

What Should You Wear on Each Kind of August Day?

Holland America’s packing list warns that “weather can shift multiple times in a day,” so one outfit won’t cover a week. Here’s the plan we’d build from the line and park service advice:

The day	Wear	Carry
Wet port day (the likeliest kind)	Light top, waterproof hooded jacket, rain pants, waterproof shoes	Dry socks, a rain cover for your daypack
Bright, dry port day	Short sleeves and light pants	Packable rain jacket, polarized sunglasses, sunscreen, SPF lip balm
Glacier day	Base layer, fleece, waterproof jacket, hat	Binoculars, thin gloves if you feel the cold
Wildlife or forest excursion	Grippy waterproof shoes, rain pants, quick-dry layers	Binoculars, small insect repellent, a waterproof bag for your phone
Denali or Fairbanks land extension	Layers you can peel off, waterproof hooded jacket	Warm fleece and hat for cold mornings

The jacket and pants. Princess’s August list calls waterproof gear a “must-have” and adds that sweaters go underneath. Holland America suggests “lightweight waterproof pants that slip over your base layers or jeans.”

The shoes. Holland America’s advice is “two pairs of durable, waterproof walking shoes,” so you have a spare when the first pair gets wet. Pack more socks than you think you need.

The sun gear. Yes, even here. Holland America says glaciers and water reflect sunlight, “increasing UV exposure even on cloudy days,” and calls polarized sunglasses “essential on bright water.”

The dinner clothes. These don’t change for Alaska. Our what to wear guide has each line’s dress code.

How Cold Does It Get on Glacier Day and Inland?

Glacier day is the one day you dress for something colder than the table suggests. The National Park Service tells Glacier Bay visitors to expect summer highs “between 50 and 60 degrees F,” a little below the 60.0°F August normal at the park station. It adds that “the moisture and cool temperatures may make it seem colder than you expect,” and says the best place to be is “outside, especially during the time near the glaciers.”

Adding a land tour? Anchorage’s August normals are 64.0°F / 50.9°F and Fairbanks’s are 66.4°F / 47.6°F, so Fairbanks has the wider swing between afternoon and night. The Denali park page gives a summer range of 33°F to 75°F, calls June through August “the rainiest months,” and warns that it “has been known to snow in any summer month.” Celebrity also says first snow at altitude is rare but possible as August ends. Bring the warm fleece.

Why Are Binoculars the Best Thing You Can Pack in August?

Because August is salmon month, and everything eats salmon. Local public radio station KFSK reports that Southeast Alaska’s pink salmon “typically” peak in early to mid-August. The park service says spawning pinks are most abundant in Glacier Bay’s streams in August, and that they feed “a wide variety” of mammals and birds. Celebrity adds that humpbacks usually stay until September and bears are “busy fattening up for winter.”

One pair per person beats sharing when a whale surfaces and dives again. Keep them in your daypack on port days, not in the cabin.

Do You Need Bug Spray for Alaska in August?

Bring a little, not a lot. Alaska.org says mosquitoes are “only really an issue” from the second week of June to the last week of July, and that they’re milder wherever there’s a breeze. Holland America still suggests a compact repellent for hikes and nature tours, because “some coastal and forested areas” have biting insects in summer. One small bottle with DEET or picaridin will do.

Could a Glacier Flood Change Your Day in Juneau?

Here’s the August quirk most packing lists skip. Each summer, meltwater fills Suicide Basin beside the Mendenhall Glacier, then bursts out. Cruise Hive refers to flooding in August 2024. The Juneau Empire reports last year’s record crest of 16.65 feet and a 14.7-foot crest on August 13, 2026, well below forecast. Public media station WHRO ranks the 2026 flood as Juneau’s fourth-largest, with little damage thanks partly to new flood walls.

Your ship is unlikely to care. Before this year’s flood, Cruise Hive reported that no line had changed its Juneau calls and that the docks sit about 10 miles from the basin, out of the water’s reach. Your excursion might care, though. Cruise Hive said hikes, kayaking and glacier viewing in the flood area could be changed or cancelled for several days, and Alaska Public Media reported the Mendenhall Glacier Visitor Center was due to close on the afternoon of August 12.

So if you’re in Juneau in early to mid-August and Mendenhall is your one big plan, have a second one. Our excursions guide covers what the fine print promises when a tour falls through.

Does Late August Need a Different Suitcase From Early August?

Slightly. The big change is the light. Here’s Juneau, from the U.S. Naval Observatory, with day lengths matching Sunrise-Sunset.org:

• August 1: sunrise 4:50 a.m., sunset 9:17 p.m., about 16 hours 27 minutes of daylight.
• August 15: 5:20 a.m. to 8:42 p.m., about 15 hours 22 minutes.
• August 31: 5:55 a.m. to 7:59 p.m., about 14 hours 4 minutes.

Holland America’s sleep mask tip is most useful early in the month, when the sun is up before 5 a.m. Late in the month, pack your fleece for evenings on deck, since it will be dark and cool after dinner.

Late August also opens the northern lights window, but only just. Travel Alaska says there’s enough darkness “by late August,” with the best viewing in the Interior and Arctic. Celebrity says the aurora needs “crisp, clear skies.” With about 19 wet days a month in Juneau, treat it as luck, and don’t pack for it.

What Can You Leave at Home?

• A heavy parka. Port lows average 48°F to 53°F. In Holland America’s words, a light waterproof shell over warm layers “beats bulky winter gear.”
• A thin poncho as your only rain gear. Princess suggests a light jacket or poncho for July. On August’s numbers, you want a real jacket.
• Snow boots. Waterproof walking shoes handle port days. If you book something specialist, check that tour’s kit list.

Before you close the zip: test the jacket in the shower at home. If it soaks through there, it won’t survive Ketchikan. Then check each port’s forecast a few days out. Normals are 30-year averages, and any one week can run far wetter or drier.

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Cruise Chaos earns nothing from cruise lines, travel agents, outdoor brands or booking links. Every fact here links to where we read it, and we downloaded the NOAA climate normals and the Naval Observatory sun times ourselves on October 30, 2026. If something has changed, tell us and we’ll correct it.

Coming up on Cruise Chaos: what to pack for a cruise, with a free checklist you can print as a PDF.

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Keep Reading

• What to Pack for a Cruise to Alaska in September, the Wettest Month of the Season
• 5 Most Forgotten Cruise Items
• How to Avoid Seasickness on a Cruise: The Cabin, the Pills and the Timing

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Sources

• NOAA NCEI: U.S. Climate Normals, 1991–2020 (monthly normals for Ketchikan, Sitka, Juneau, Skagway, Seward, Glacier Bay, Anchorage and Fairbanks stations, retrieved October 30, 2026)
• Wikipedia: Juneau, Alaska (climate table, NOAA 1991–2020)
• Wikipedia: Ketchikan, Alaska (climate table, NOAA 1991–2020)
• U.S. Naval Observatory: Sun and Moon Data for One Day (Juneau, August 1, 15 and 31, 2026)
• Sunrise-Sunset.org: Juneau, Alaska
• National Park Service: Glacier Bay, Cruise Ship Visitors
• National Park Service: Glacier Bay, Pink Salmon
• National Park Service: Denali, Weather
• Holland America Line: Alaska Cruise Packing List
• Princess Cruises: What to Pack for an Alaska Cruise (updated December 16, 2025)
• Royal Caribbean: Alaska Cruise Weather by Month (published May 28, 2026)
• Celebrity Cruises: Best Time to Cruise Alaska (updated October 8, 2026)
• Celebrity Cruises: Northern Lights From a Cruise Ship in Alaska
• Travel Alaska: Top Reasons to Visit Alaska in the Fall
• Alaska.org: Mosquitoes in Alaska
• KFSK: Southeast Pink Salmon Catches Trickling In (July 30, 2018)
• Cruise Hive: Juneau Braces for Glacier Flooding as Dozens of Cruise Ships Head In (August 1, 2026)
• Juneau Empire: Suicide Basin Waters Expected to Crest by 6 p.m. Thursday (August 13, 2026)
• Alaska Public Media: Updates for Juneau’s 2026 Glacial Outburst Flood
• WHRO: On a Melting Glacier in Alaska, There’s Something Most People Will Never See (September 23, 2026)