Real-time WBGT, flag levels and 14-day forecasts in your pocket.
Every guide on the site, grouped by who it is for. Each one covers wet bulb globe temperature for a specific setting: what the thresholds are, who takes the reading, and what has to change when the number climbs.
WBGT basics and tools
The measurement explained: the four inputs, the weighting, and what the number means.
Work out WBGT from weather data or from three thermometer readings.
How the index is built, what range it runs over, and how to read a value.
The full WBGT level chart in Fahrenheit and Celsius, with activity guidance.
White, green, yellow, red and black flags, and what each one requires.
Why the two numbers differ and which one your policy actually requires.
Sports and athletics
How WBGT drives practice modification across every outdoor sport.
Turn today's conditions into a practice plan, sport by sport.
Pads, helmets and August two-a-days: the hardest WBGT case in sport.
Equipment-adjusted thresholds for football practice.
State rules, preseason acclimatization and what parents should ask.
What athletic trainers monitor, and the NATA position stand behind it.
Work-to-rest ratios, break length and equipment calls by WBGT.
Work, OSHA and construction
How OSHA treats heat, and where WBGT fits in the General Duty Clause.
Screening against ACGIH TLV and action limits by workload.
Building a heat illness prevention plan around a measured number.
Putting WBGT in every supervisor's pocket across a crew or a site.
Concrete, roofing and steel: the hottest surfaces on any job.
Why the reading at the jobsite differs from the airport forecast.
Work-rest cycles and water targets from a single reading.
WBGT, heat index, humidex and TLV compared in one place.
Continuous heat stress monitoring without a dedicated instrument.
Military and first responders
Heat categories 1 to 5, work-rest tables and water intake guidance.
Category and work-rest cycle from a reading, with uniform correction.
Clothing adjustment factors and acclimatization in heat planning.
The full heat category table with flag colors and water limits.
Schools, band and childcare
One policy that covers athletics, band, PE and recess.
Checking the number before practice, rehearsal, PE or recess.
State association rules and who takes the reading.
The Texas UIL wet bulb globe temperature policy, explained.
Outdoor play decisions for infants and toddlers in the heat.
Playground heat, surface temperature and pre-K outdoor time.
State rules by athletic association
Which state athletic associations require WBGT, and how the thresholds differ.
By-Law 2.67: statewide thresholds, cold immersion tubs and a fine for violations.
Policy 41 and the Zachary Martin Act, including per-sport rules for contests.
A stricter scale that suspends practice at 90°F and bars unconditioned athletes at 85°F.
The 15-minute ratchet rule, device recalibration, and why apps are not accepted.
Two regional threshold sets, and the rare policy that explicitly permits apps.
WBGT preferred with heat index allowed as a fallback, on paired thresholds.
The 2026 mandate, hourly readings, and free smartphone apps accepted.
Know the real heat number
Real-time WBGT, flag levels and forecasts. Free on iPhone.
