PNW Mushroom Conditions

Coordinates:

Current Overall Mushroom Conditions

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Vegetation Type

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LANDFIRE EVT 2025

Seasonal Metrics —

Current Date: —

Summer — Mean Daily Temperature: —

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1991–2020 Summer Mean Daily Temperature: —

Rainfall —

Rain — last 14 days: —

Rain — last 30 days: —

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Rain — last 3 days: —

Rain — last 7 days: —

Days since meaningful rain: —

Soil Conditions —

Surface soil moisture (0–7 cm) Current: —

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Surface soil moisture (0–7 cm) 7 days ago: —

Surface soil temperature (0–7 cm) Current: —

Air Temperature —

7-day average temperature: —

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7-day average nighttime low: —

Frost days in last 7 days: —

Hard Freeze days in last 7 days: —

Atmospheric Moisture —

7-day average relative humidity: —

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7-day average dew point: —

Mushroom Conditions Score

The Mushroom Conditions Score is a 0–100 estimate of how favorable current conditions are for autumn mushroom fruiting in the Oregon Coast Range, with particular emphasis on Pacific golden chanterelles. The weights are informed by Pacific Northwest research, but the exact percentages and scoring thresholds are our heuristic model, not coefficients established by the studies.

The basic philosophy is that the season sets the stage, rainfall drives fruiting, soil moisture confirms that water is available, air temperature determines whether conditions remain suitable, and humidity helps preserve those conditions.

Seasonal Conditions (25%)

Seasonal conditions establish whether the location is biologically within the established seasonal fruiting window. This combines time of year with the preceding summer's temperature relative to the 30-year average.

Season receives substantial weight because chanterelle fruiting has a strong seasonal pattern in the Pacific Northwest. A long-running Oregon study in the Bull Run watershed found a statistically significant positive relationship between warmer summer temperatures and subsequent chanterelle abundance. U.S. Forest Service research also notes that chanterelles in western Oregon rarely fruit before mid-September at some study sites, although timing varies considerably with site and weather.

Rainfall (30%)

Rainfall is the largest individual component because autumn precipitation appears central to initiating and supporting fruiting. We emphasize cumulative rainfall over the preceding 14 and 30 days, rather than simply asking whether it rained yesterday.

The Oregon Cantharellus Study found that warm summers followed by relatively wet autumns produced more chanterelles, with a positive relationship between fall precipitation and abundance. The Forest Service's broader synthesis also notes that rainfall during primordia formation supplies water needed for mushroom growth.

Soil Conditions (20%)

Soil conditions represent whether precipitation has actually translated into a moist forest floor capable of sustaining fruiting. The score primarily considers current shallow soil moisture, with a smaller contribution from the recent trend of shallow soil moisture: whether the soil has been getting wetter or drier over the previous week.

This is useful alongside rainfall because identical rainfall totals can produce different ground conditions depending on antecedent dryness, drainage, vegetation, and other factors. Forest Service research specifically identifies high soil humidity during the fruiting season as helping chanterelles continue growing without drying out.

Air Temperature (15%)

Air temperature measures whether recent temperatures are suitable for fruiting and whether frost or hard freezes are beginning to suppress the season.

Temperature matters substantially, but we give it less weight than moisture because suitable temperatures without adequate moisture won't produce good conditions. Pacific Northwest research treats weather as an important driver of year-to-year chanterelle production, and Forest Service studies have investigated air and soil temperature alongside moisture variables when examining chanterelle production.

Atmospheric Moisture (10%)

Atmospheric moisture is primarily a drying and preservation modifier. High relative humidity helps the forest floor and existing fruiting bodies retain moisture between rainfall events.

We give this the lowest weight because much of the underlying moisture environment is already captured by rainfall and soil moisture. It adds useful information about drying conditions but should not allow humid air to compensate for genuinely dry soil. Chanterelles are unusually slow-growing and persistent—Forest Service synthesis reports growth on the order of centimeters per month and fruiting bodies persisting for weeks—making protection from drying potentially meaningful.

Data Resolution and Map

Weather data comes from Open-Meteo and represents gridded weather-model data rather than measurements taken at the exact coordinates selected on the map. The historical conditions used for most of the score are approximately 9 km resolution, while forecast data generally resolved substantially closer, with a median offset of about 1.3 km.

The red bullseye indicates the location that was entered for Check Conditions. The 9 km circle surrounding the red bullseye on the map illustrates the approximate surrounding area over which the weather data should be interpreted.

Click anywhere on the map to choose a location. A white dot will mark your selection, and the coordinates will automatically appear in the Coordinates box, ready for checking conditions.

There are three map base layers to choose from: streets, USGS topographic maps, and satellite imagery with topographic features. An additional USGS surface geology layer can be displayed on top of any base map. Because of the level of detail, the geology layer is only displayed when the map is sufficiently zoomed in.

Vegetation Type

Vegetation data is pulled from USFS and USGS LANDFIRE Existing Vegetation Type (EVT) 2025 dataset that classifies areas into detailed ecological systems based on characteristic plant communities. While the project was originally for wild fire managment, it has become useful for a host of research and land management projects. LANDFIRE produces its vegetation classifications using predictive landscape models informed by field-reference data, Landsat satellite imagery, elevation, and other environmental data. The dataset is mapped at approximately 30-meter resolution.

Brief Bibliography

Pilz, D., Norvell, L., Danell, E., & Molina, R. (2003). Ecology and Management of Commercially Harvested Chanterelle Mushrooms. USDA Forest Service, Pacific Northwest Research Station, General Technical Report PNW-GTR-576.
USDA Forest Service publication
Norvell, L. L., & Roger, J. (1998). The Oregon Cantharellus Study Project: Pacific Golden Chanterelle Preliminary Observations and Productivity Data (1986–1997). Inoculum 49(2): 40. Research conducted in Oregon's Bull Run watershed examining chanterelle productivity, seasonality, temperature, and weather.
Oregon Cantharellus Study Project
Norvell, L. L., Roger, J., Lindgren, J., & Kopecky, F. (1996). “Study 8: Oregon Cantharellus Study Project, 1986–1996.” In Managing Forest Ecosystems to Conserve Fungus Diversity and Sustain Wild Mushroom Harvests, USDA Forest Service, Pacific Northwest Research Station, GTR-371, pp. 69–72.
Washington State University Magazine (2020). “Pacific Golden Chanterelles.” Includes practical guidance from retired WSU Extension specialist Jim Freed regarding late-summer temperatures, soil moisture, rainfall, fruiting season, and frost.
Pacific Golden Chanterelles — WSU
Open-Meteo. “About Open-Meteo.” Open-Meteo is an open-source weather-data platform that makes open meteorological data from national weather services accessible through a unified API. It integrates local and global numerical weather models and provides weather forecast and historical data for use in applications and research.
Open-Meteo — About
LANDFIRE. “Existing Vegetation Type.” U.S. Department of Agriculture, Forest Service and U.S. Department of the Interior. Describes the LANDFIRE EVT ecological-system vegetation classifications and provides access to the attribute tables and data services.
LANDFIRE Existing Vegetation Type
U.S. Geological Survey. “Cooperative National Geologic Map: Earth’s Surface Geology.” National Cooperative Geologic Mapping Program. National synthesis of surface geologic mapping compiled from USGS and state geological survey source maps
USGS Cooperative National Geologic Map — Earth’s Surface Geology

7-Day Mushroom Outlook

Forecast mushroom conditions for each of the next seven days. Each score treats that day as a temporary “today” and combines projected seasonal conditions, rainfall, soil moisture, air temperature, and humidity.

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