Are there mosquitoes in Alaska? Plenty in June and July, and almost no disease.

Yes, and in June and July there are a lot of them. Snowmelt mosquitoes swarm in the Interior and on the tundra, with black flies near rivers and no-see-ums on calm evenings, while the cruise ports and the Anchorage area tend to be milder. None of it carries a disease you need to plan around.

June and July inland

Alaska's mosquitoes hatch as the snow melts and peak in June and July. Most are large snowmelt Aedes species, which tend to bite in daylight as well as at dusk. They are worst on warm, calm days and in the evening, and wind, cold and rain keep them down. A 2026 study of caribou on the Arctic tundra along the Yukon border found that mosquito harassment was limited below about 50°F (10°C), above about 72°F (22°C) and in wind over about 16 mph (7 m/s). Numbers fall through August, and September after the first frosts tends to be quiet. A wet, warm spring makes for a bad summer.

The Interior has the worst reputation. Wonder Lake and Kantishna, at the far end of the Denali park road, are known as the park's mosquito spots. The wet forest and muskeg around Fairbanks and Talkeetna have a similar reputation, and open tundra can swarm on any still day. If you can, save Wonder Lake for a breezy or cool day.

Two smaller biters join in. Black flies, which Alaskans call white socks, breed in running water and bite by day, and they crawl into cuffs and hairlines, so tuck in and cover up near rivers. No-see-ums, called punkies locally, are tiny biting midges. They are weak fliers grounded by wind and tend to go for ankles and lower legs at dawn and dusk. Our Scotland midge briefing explains how wind and weather drive biting midges. Forum posters add horse flies in late summer.

Cruise ports and the coast

Cruise passengers who stay in the Inside Passage towns or out on the water seldom need more than a small bottle of repellent, posters say. The bites come on inland hikes, such as Dyea outside Skagway and the trails up Mount Roberts in Juneau, so put repellent on before you head up. Anchorage and the Kenai Peninsula have a reputation for being milder than the Interior, though forest trails there still have mosquitoes in June and July. If your cruise adds a land tour to Denali or Fairbanks, pack for the Interior.

Disease is a footnote

CDC's national West Nile data show no locally acquired case in Alaska, and there is no dengue, chikungunya, Zika or malaria, so no vaccine or medicine is needed. Two other mosquito-borne viruses, Jamestown Canyon and snowshoe hare, show up in Alaska as antibodies in old blood-test surveys of people who live and work outdoors, the newest from samples taken in 2007, and illness is rarely diagnosed. Ticks are a small item. Alaska has historically been outside the range of the lower 48's main disease-carrying ticks, and testing in 2019–2020 found no known human pathogens, though a tick check after walks through brush is still a good habit.

Where you're going

How the main stops on a land-and-sea trip compare for June–September.

For other northern bug seasons, our Canada briefing covers Churchill's July swarms and the June black flies of Ontario cottage country, and our Greenland briefing covers the tundra around Kangerlussuaq.

What travelers report

Paraphrased from TripAdvisor and Cruise Critic threads and linked so you can read them in full. Neither is dated, and how bad a summer gets swings a lot from one year to the next.

• Denali National Park · summer

  A reply said the main mosquito trouble spot is Wonder Lake and Kantishna at the far end of the park road, and visitors who do not go that far will probably be fine; places nearer the entrance such as Healy can still be bothersome in a bad year. Another stressed that mosquito levels swing a lot from season to season. TripAdvisor ↗

• Alaska cruise ports (Skagway) and Fairbanks land tours · June-July

  Asked whether July brings a mosquito problem, replies said the bugs were worst inland: one poster was bitten hard near Dyea outside Skagway in June, and another on a late-June cruise found the ports fine but met bugs in Skagway and on Fairbanks-area tours. Cruise Critic ↗

As on any trip, a fever during or after it means a doctor visit, and you tell them where you were, including where you hiked or camped.

Traveler questions