HeatIndexF · engineering calculator
HeatIndexF noaa heat index
Know the apparent heat-index temperature for outdoor work planning on hot humid days
Result
NOAA Rothfusz regression HI(T,RH) with screen limited to T≥80°F and RH≥40%
How to use this estimate
NOAA Rothfusz regression HI(T,RH) with screen limited to T≥80°F and RH≥40%. Exact algorithm evidence: NWS Heat Index Equation (Rothfusz regression) page. Publishes the Rothfusz heat-index regression HI(T,RH) used by this screen. Approximate Rothfusz screening only within the stated hot-humid envelope — not a heat illness medical protocol. Out of scope as listed — not a stamped design.
Sources, methodology, and assumptions
Methodology
NOAA Rothfusz regression HI(T,RH) with screen limited to T≥80°F and RH≥40%
Assumptions
Hot humid outdoor air; Primary Rothfusz polynomial only; Not a medical tool. Informational estimate.
Out of scope
full NWS adjustment branches below 80°F; heat illness medical protocol; wet-bulb globe temperature; indoor HVAC design
Sources
- NWS Heat Index — NOAA/NWS
- NWS Heat Index Equation (Rothfusz) — NOAA/NWS
Last technically reviewed: 2026-09-11