Glossary
The legal terms that show up in class action notices, explained in two sentences.
Heat Index
The apparent temperature combining air temperature and relative humidity, as published by the NWS using the Steadman formula.
Wet-Bulb Temperature
The lowest temperature evaporative cooling can achieve under current humidity, measured by a thermometer wrapped in a wet cloth.
Feels-Like Temperature
A general-purpose apparent temperature, formula varies by weather provider.
Heat Exhaustion
A heat illness with core body temp 100 to 103 F, marked by heavy sweating and weakness, treatable with cooling and fluids.
Heat Stroke
A life-threatening heat illness with core body temp above 104 F and altered mental status. Cool aggressively within 30 minutes of collapse.
Heat Advisory
An NWS bulletin issued when forecast heat index will reach 100 to 105 F (regional threshold) for 2+ hours within 36 hours.
Excessive Heat Warning
An NWS bulletin issued when forecast heat index will reach 105 to 110 F (regional threshold) for 2+ days, signaling severe risk.
WBGT (Wet-Bulb Globe Temperature)
A composite heat metric used by athletic governing bodies and the US military, factoring in temperature, humidity, sun, and wind.