This layer shows the total number of poultry-relevant heat wave days recorded per pixel across Maryland and the surrounding mid-Atlantic region over the 2000 to 2023 study period. Heat wave days are identified using a custom poultry-based index that combines absolute temperature thresholds, percentile-based relative temperature thresholds, and a relative humidity condition tailored to broiler chicken physiology in Maryland. A day qualifies under the absolute conditions when the daily minimum temperature is at or above 25°C (77°F) and the daily maximum temperature is at or above 32.5°C (90.5°F). A day qualifies under the relative conditions when both the daily maximum and minimum temperatures exceed the 90th percentile for that calendar day and relative humidity is at or above the 50th percentile. A minimum of three consecutive qualifying days is required for an event to be classified as a heat wave. Higher values indicate areas that have experienced a greater cumulative number of heat wave days and therefore greater sustained exposure to conditions likely to induce heat stress in broiler chickens.
The data is derived from ERA5-Land reanalysis data at 9km resolution, covering May through September for each year from 2000 to 2023. The heat wave index was calculated and mapped using Esri ArcGIS Pro.
- Source: University of Maryland
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