Mushrooms need moisture to develop; most species prefer temperatures of 40-70°F. In every region there is an optimum period, the “mushroom season,” when most of the mushrooms appear. In the far north, high mountains, deserts, and other places with severe climates, the “window of opportunity” is compressed into a few weeks. In milder climates, especially along the coast, it may span several months or more than half the year. The peak mushroom season for each region is given below. Of course, each year is a little different; the season may be “early” or “late” depending on rainfall and temperature patterns.
Alaska: August–mid September
Sierra Nevada, Cascades, Rocky Mountains: late July–early September (after thundershowers)
Lower mountains and foothills of higher ranges: September–November or until the first heavy frosts
Pacific Northwest: September–November
Northern California Coast: October–January
Central California Coast: November–March
Southern California Coast: December–March (but very erratic)
Central Valley of California: October–January
Southwest: late July–September
Deserts: sporadic (whenever it rains).
In many areas, especially those with a snowpack during the winter, a smaller flush of mushrooms appears in the spring. Certain species such as morels are abundant at this time but rare or absent during the main mushroom season.
As the mushroom season unfolds, you will notice a succession or procession of different mushrooms. Just as certain wildflowers bloom before others, the king bolete fruits early in the season, while the hedgehog mushroom appears much later, and the chanterelle can be early or late. However, the sequence may vary from region to region and from year to year. Much of the “sport” of mushroom hunting lies in learning the habits of your favorite mushrooms. As in the larger world, timing is everything: a few days early, and they will be invisible, still under the mulch; too late, and they will be gone or “occupied by other tenants” (see this page).