CAP WxCOP
WBGT CALCULATOR
Environmental Inputs
Dewpoint in °F (same unit as temp)
hPa
UTC
Enter location and time to compute solar elevation.
Method: Liljegren outdoor WBGT (USARIEM standard) · Stull wet bulb approximation
Solar DSWRF: Spencer (1971) declination · hour angle → elevation → clear-sky × cloud fraction
Globe temp: radiation + wind correction · WBGT = 0.7·Tw + 0.2·Tg + 0.1·Ta
Authority: CAPR 60-2 (governing) · DAFI 48-151 Ch.4 Table 4.1 (WBGT flag thresholds)
WBGT
°F (Outdoor Liljegren)
Enter values and calculate
DAFI 48-151 Ch.4 Table 4.1 — Activity Guidance
Flag WBGT °F Easy Moderate Hard / PT
<78 No limit No limit No limit
White 78–81.9 No limit No limit 40 min/hr
Green 82–84.9 No limit No limit 30 min/hr
Yellow 85–87.9 No limit 40 min/hr 20 min/hr
Red 88–89.9 No limit 30 min/hr 10 min/hr
Black ≥90 No limit 20 min/hr Rest only
Wet Bulb Temp
Globe Temp
Heat Index
Wind Chill
Heat index and wind chill shown for reference only.
WBGT is the authoritative metric for heat stress assessment.
Rest periods include adequate water intake per CAPR 60-2.