Index Mushroom Calendar

Index sits in the North Cascades and one of the wetter corners of the region, with roughly 109.9 inches of annual rainfall, most of it falling in the cool months from fall into spring. The ground warms and reaches early fruiting potential around April, by which point the average last frost (Apr 14) has usually passed. Rain barely lets up even at the height of summer, so something is usually fruiting, though the heaviest push still comes with the fall rains. The first frosts around Oct 29 eventually close the main season, though hardy cool-season species hang on.

Best months September, October, and December
Ground warms ~April
Frost-free Apr 14 – Oct 29
Annual rain 109.9"
Species tracked 1

What Fruits When Near Index

JFMAMJJASONDMorelregSpring KingregKing BoleteregChanterelleOysterregLobsterregBear's HeadregShaggy Manereg

Shading shows when each species typically fruits within about 10 miles, not abundance. Based on iNaturalist observation trends. reg = pooled from the surrounding area where local sightings were sparse.

The Shape of the Season

All species combined — local observations within about 10 miles, by month.

Weather Through the Year

Average daily high–low (°F)

Average monthly precipitation (inches)

The Forest Around Index

Dominant tree species within about 10 km — the hosts that shape which mushrooms grow here.

  • Western Hemlock40.4%
  • Douglas-fir25.3%
  • Red Alder17.9%
  • Sitka Spruce12.9%
  • Bigleaf Maple3.4%

Species to Know Near Index

Chanterelle Chanterelle Peaks in October Photo: Jeremy Collison (CC BY-NC)

Common Questions

When is mushroom season in Index?

Near Index, most mushroom activity arrives with the fall rains. The strongest months in the local observation record are September, October, and December.

When do morels fruit near Index?

Morel reports in the surrounding region peak in April, May, and June. Timing tracks soil temperature, so south-facing slopes and lower elevations start earlier and higher ground runs later.

What mushrooms grow near Index?

1 species show up in the observation record within about 10 miles of Index, including Chanterelle. The calendar above shows when each one typically fruits.

Want live conditions instead of climatology? The Forayz map layers soil moisture, soil temperature, snow cover, and recent burns over the same area.

Nearby Calendars in Washington

Climate normals: NOAA NCEI U.S. Climate Normals (1991–2020). Season-onset timing is an air-temperature proxy, not a soil reading.