Several U.S. states are due some winter weather this June as the National Weather Service (NWS) issues a slate of snow and frost warnings.

Despite the time of year, wintery weather is set to strike across parts of the western and northern United States this weekend, with forecasters warning of heavy snowfall in Alaska's Brooks Range and frost across portions of Northern California and southern Oregon, as well as parts of Idaho and Washington.

Alaska

A Winter Storm Watch has been issued for Alaska's Central Brooks Range from Saturday evening through Monday evening, with forecasters warning of moderate to heavy snowfall and blowing snow. Snow accumulations of 6 to 12 inches are possible, with locally higher amounts at higher elevations, while wind gusts could reach 30 mph.

The greatest impacts are expected along the Dalton Highway corridor, including Atigun Pass, where stronger winds may create areas of blowing snow and significantly reduce visibility. Travel conditions could become hazardous, particularly from Sunday into Monday when the heaviest snowfall is forecast.

The NWS says an unusually strong Arctic trough is expected to move across the North Slope and Brooks Range during the weekend and into early next week, bringing widespread snow to northern Alaska and the heaviest accumulations to the mountainous terrain of the Brooks Range.

The Central Brooks Range, which extends out of Alaska and into Canada's Yukon Territory, is one of several places in the United States where accumulating snow can occur in any month of the year because of its high elevation and Arctic location. Areas such as Atigun Pass, Galbraith Lake and the higher elevations along the Dalton Highway can see snow even during summer.

California and Oregon

A Freeze Warning and Frost Advisory remain in effect from 2 a.m. to 9 a.m. PDT Sunday across portions of Northern California and southern Oregon, including parts of Klamath and Lake counties.

The Freeze Warning covers the Klamath Basin and Winter Rim areas, where temperatures could fall as low as 22°F. Communities affected include Crescent, Chemult, Chiloquin, Fort Rock, Silver Lake, Sprague River, Beatty, Bly, Keno, Midland, Altamont, Dorris and Macdoel.

Meanwhile, the Frost Advisory is in effect for eastern Lake County and southern Klamath County, including areas around Summer Lake, Alkali Lake, Paisley and Merrill, where temperatures are expected to drop to around 32°F, creating conditions favorable for frost formation.

The NWS warned that freezing temperatures and frost could damage or kill crops and other sensitive vegetation, while also posing a risk to unprotected outdoor plumbing. Residents are being urged to take precautions to protect plants and animals vulnerable to the cold.

The Klamath Basin, northern Klamath County, and Lake County sit at relatively high elevations, thousands of feet above sea level. Because of the dry air and long nights, temperatures can plunge, resulting in frost and sometimes snow, even after warm daytime conditions in the summer months.

Idaho and Washington

A Frost Advisory has been issued for parts of northeastern Washington and northern Idaho from 10 p.m. Saturday through 11 a.m. Sunday, with temperatures expected to fall between 29°F and 36°F.

The advisory covers a broad area including the Okanogan Highlands, Okanogan Valley, Northeast Mountains and Northern Panhandle regions, encompassing communities such as Winthrop, Twisp, Omak, Republic, Colville, Newport, Deer Park, Sandpoint and Bonners Ferry.

The NWS warned that the cold overnight temperatures are likely to result in frost formation, posing a threat to sensitive outdoor vegetation. Residents are being advised to take precautions to protect vulnerable plants, as some may be damaged or killed if left uncovered.