‘Frosty fall’ and October snow: Here’s what the Farmers’ Almanac says to expect in Idaho

On Sept. 22, the sun will align perfectly with the equator, giving the northern and southern hemispheres an equal amount of sunlight and signaling the Autumnal Equinox, which signals the astronomical start of fall.

After a scorching summer that saw Boise record its hottest-ever August and second-hottest-ever meteorological summer, cooler weather will relieve many Idahoans.

But when will the temperatures cool down for good, and should the Pacific Northwest expect snow before we hit winter-proper?

Fall forecast

Farmers’ Almanac, which predicts long-range weather forecasts and boasts an 80-85% accuracy in its forecasting, is expecting a frosty fall with typical precipitation for the Northwest.

Farmers’ Almanac groups states into regions for its forecast — Idaho falls in with Washington and Oregon as part of the Northwest region.

Typical precipitation for Boise would be 0.55 inches in September, 0.82 inches in October and 1.3 inches in November. The average high temperature in Boise at the start of September is 86 degrees — but the city has already hit or exceeded 100 degrees four times this month, reaching 104 degrees on Wednesday, Sept. 7, the highest ever recorded in Boise in September. The average will drop to 42 degrees by the end of November.

Before Boise hits the frigid weather, the City of Trees will look its best throughout October. Farmers’ Almanac forecasts that the best time to see fall foliage throughout Idaho will be Oct. 5-21.

But if Farmers’ Almanac’s snow forecast is correct, the fall foliage window will remain tight before the snow comes down and covers the leaves.

The first snowfall of the season for Idaho is forecast for Oct. 20-23 — although the forecast doesn’t specify exactly where in Idaho, that weekend kicks off a busy weather month that’ll see “very unsettled weather” in the first few days of November and “fair, then stormy” weather throughout the middle of the month.

When to hit the road and when to stay home

Looking for an ideal time to vacation before it gets too cold?

Sept. 12-19 will be the best time to vacation this month. Otherwise, you may have to wait until the first week of October, which is forecast to be “fair and dry” from Oct. 1-3 before turning to “very unsettled weather.”

Much of October and November will be meteorologically active in the Northwest, with the only extended reprieve from stormy weather coming Oct. 8-11, Nov. 4-7, and Nov. 28-30.

Thanksgiving Week is forecast to have scattered showers and snow in the upper elevations from Nov. 20-23, and then a small break in the rain before more storms, gale force winds, and heavy snow in the mountains will sweep over the Gem State from Nov. 24-27.

The skies will clear for December with the occasional storm coming inland from the Pacific Ocean and stormy along the coastal plain for Christmas.