The ForageIQ Engine

Western: 0.3"+ precipitation in 7 days, or active snowmelt from SNOTEL SWE decline. Eastern: 0.5"+ rain in 3 days. Species-specific: boletes need 2"+ then 7-10 days; chanterelles need 2-4" over 6-13 weeks (Ivanochko 2021); morels need >10mm events in prior 30 days (Mihail 2007). Hard limit: dry soil means no fruiting regardless of temperature, so without the trigger the grade is at most Poor.

Judged per in-season species against that species’ own soil-temperature minimum: the soil must be at or above it today and on at least 5 of the last 7 days (Schmidt 1983, Mihail 2007: mycelium needs 5-7 days of warm soil). Western soil temps from SNOTEL at 2"; eastern from SCAN at 4"/10cm or the NWS air-temp model with canopy adjustment. If no in-season species is primed yet, the grade is at most Fair.

At least one tracked species is inside its fruiting window and its elevation band overlaps the region, based on elevation-specific phenology data parsed from the codex. If nothing is in season here, the region is Very Poor — there is nothing to fruit.

No forecast temperatures below 32°F in the next 48 hours. A single hard freeze can reset a flush, so a freeze in the forecast caps the grade at Fair — and so does a night at or below 28°F in the past week: it kills the fruiting bodies already up, while the soil stays warm enough to look primed for days afterwards. A new flush takes one to two weeks.

Per the US Drought Monitor. Extreme or exceptional drought (D3/D4) caps the grade at Poor; severe drought (D2) drops it one grade.

Dry wind (≥ 4 m/s at 10m — a persistent drying breeze at fruiting height once the canopy slows it) coinciding with low relative humidity (< 40%) at the same hour rapidly strips moisture from fruiting bodies — mushrooms lack stomata or cuticle and lose water far faster than plants. We count the hours of simultaneous dry-wind exposure in the trailing 72 hours: 12+ hours is high risk and drops the region one grade; 4+ hours is moderate risk and rules out Excellent.