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.