A four-layer pressure model for indoor cannabis cultivation
The EBI answers a specific question cultivators face every day: how much pressure is the outside environment putting on your facility right now, and what should you do about it? It combines weather, geography, climate context, and seasonal position into a single 0–100 score and a five-tier operating posture.
EBI scores run from 0 to 100: higher is better, 100 means conditions are optimal for cultivation (no environmental burden), 0 means conditions are least favorable for cultivation (maximum environmental pressure).
EBI tier boundaries are derived from a statistical analysis of 32,232 baseline scores computed across 2,686 representative US locations and 12 months of 30-year NOAA climate normals. Boundaries are set at natural breaks in the score distribution with a conservative downward bias — meaning borderline conditions are classified into the more cautious tier. Thresholds are reviewed and updated when new coverage data is added.
Current conditions and 7-day forecast — humidity, temperature, rain, and wind — drawn from the National Weather Service with Open-Meteo as a secondary source for broad data coverage. Weather is the most time-sensitive layer: it changes hourly and has the highest weight in the model.
Cropland, wetlands, forest, and urban land within 5 miles of your ZIP, sourced from the USGS National Land Cover Database. Land composition affects ambient spore load — a facility bordered by wetlands faces different baseline pressure than one in an industrial zone. Geography is stable year-round; it reflects the structural characteristics of your facility's environment, not today's conditions.
Your area's typical conditions for this month, drawn from 30 years of NOAA records (1991–2020). This is what "normal" looks like for your location and time of year. The climate baseline provides the reference frame that makes today's weather interpretable: a 75% humidity reading means something different in coastal Maine than in the Sonoran Desert.
How today's conditions compare to the 30-year monthly normal for this ZIP. A humid day in a dry climate reads differently than the same humidity in a region that is always humid. Seasonal context captures the deviation signal — conditions that are unusual for your location and time of year warrant more attention than conditions that are typical.
The EBI score is a weighted composite of six components, each targeting a distinct dimension of environmental pressure relevant to indoor cannabis cultivation. Component weights are grounded in published pathology thresholds for Botrytis cinerea and Aspergillus species.
Environmental moisture — humidity and precipitation together — carries the most weight in the EBI composite, reflecting the dominant role water activity plays in fungal biology. Temperature follows as both a direct factor and a biological gate: humidity's contribution to EBI is scaled by temperature, because the molds most relevant to cannabis cultivation require a minimum thermal threshold to sporulate actively. High humidity in cold air carries far less biological significance than the same humidity in the 60–80°F range, and the model reflects that distinction explicitly.
Wind speed contributes as a spore transport factor — meaningfully amplifying risk when conditions already favor sporulation, and minimal when they don't. Seasonal context and land use provide background calibration that makes current readings meaningful relative to historical norms for your specific region.
Factor weights are calibrated to reflect the relative biological significance of each variable in promoting fungal sporulation and spore viability, with reference to published plant pathology research on the Northeast cannabis pathogen profile. They are periodically reviewed as new cultivation data informs the model.
The primary driver of the model. Current relative humidity is evaluated against fungal sporulation thresholds — high humidity is the single strongest predictor of elevated outdoor biosecurity pressure. Source: NWS / Open-Meteo.
A secondary driver. Temperature is scored by its deviation from the optimal growth window for common cannabis pathogens. Conditions near that window elevate pressure; conditions far outside it reduce it. Source: NWS / Open-Meteo.
A secondary driver, weighted similarly to temperature. Rain volume serves as a spore-mobilization proxy — wet conditions lift and transport spores that would otherwise remain dormant. Source: NWS / Open-Meteo.
A meaningful supporting signal. This component captures how much current conditions deviate from the 30-year monthly climate normal for your location — unusual conditions warrant more attention than typical ones. Source: NOAA Climate Normals 1991–2020.
A supporting factor. Wind speed is used as an airborne transport risk factor — higher wind speeds increase the radius over which outdoor spores can reach facility intake points. Source: NWS / Open-Meteo.
A structural baseline factor. Cropland, wetlands, forest, and urban cover within 5 miles of your facility contribute a stable ambient spore load estimate that does not change day to day. Source: USGS National Land Cover Database.
Fungal risk in cannabis cultivation is not simply the sum of individual environmental factors — it is the product of their co-occurrence. High humidity alone is not dangerous. High humidity at the right temperature, following recent rainfall, with active wind transport — that is an outbreak condition.
EBI identifies when outdoor conditions simultaneously enter a documented pathogen pressure window: a combination of environmental factors known from plant pathology research to produce elevated infection risk for a specific organism. When a window is active, EBI names it and generates recommendations calibrated to that specific threat rather than the score tier alone.
Botrytis cinerea is the primary calibration reference for the Northeast cannabis pathogen profile. B. cinerea — the cause of gray mold — is the most economically significant fungal pathogen affecting cannabis cultivation in the region. Its documented optimal sporulation range of 60–77°F (15–25°C) at relative humidity above 80% defines the Botrytis Active Window. When outdoor conditions enter this range following significant precipitation, EBI identifies a Botrytis Wet Stack condition — the simultaneous occurrence of active germination temperature, high humidity, and rainfall-driven spore dispersal that plant pathology literature consistently associates with peak infection events.
Aspergillus species — the cause of aflatoxin and ochratoxin contamination responsible for cannabis testing failures — become the primary concern at higher temperatures. The Aspergillus Heat Window activates when temperature and humidity enter the documented sporulation envelope for A. flavus and A. fumigatus, consistent with published food safety and agricultural research on this genus.
At extreme temperatures, B. cinerea activity is suppressed by documented heat inhibition of conidial germination. EBI reflects this suppression in the composite score, shifting primary concern toward Aspergillus in hot-humid conditions.
Window trigger conditions are derived from published plant pathology literature. Scoring is calibrated from biological first principles and will be refined as facility outcome data accumulates.
EBI uses live weather observations as its primary input. When live data is available from the National Weather Service or Open-Meteo, the score reflects current conditions. Each component is tagged in the API response with its data source so the origin of each input is always traceable.
When live observations are unavailable for a specific component, EBI substitutes that component's 30-year monthly average for the location — the same climate normal used for seasonal context. The widget discloses when this occurs. A score computed entirely from modeled data is still a valid estimate of typical conditions for that location and time of year; it simply does not reflect today's specific weather.
In rare cases where weather data cannot be retrieved from any source, EBI will display a service unavailability message rather than return an estimate. We do not fabricate scores. If you see this message, checking back in a few minutes will typically resolve it.
EBI covers the contiguous United States. ZIP codes in Hawaii, Alaska, and US territories return an out-of-coverage response. Full US coverage is a post-R1 enhancement.
EBI does not predict rain or temperature. It translates environmental conditions into cultivation-relevant pressure — the same conditions mean different things depending on your geography, your climate, and the time of year. A 65°F day with 80% humidity in coastal Maine in October reads very differently than the same numbers in Phoenix in July. EBI captures that difference; a weather app does not.
EBI measures outdoor environmental pressure. Actual conditions inside your facility depend on your HVAC, filtration, sealing, and operations. EBI tells you what's coming in from outside so you can calibrate your response — it does not replace sensors, environmental controllers, or IPM protocols.