Discomfort Index & Heat Index Calculator
Move temperature and humidity to instantly update the discomfort index, the heat index (apparent temperature), and your heat illness risk level.
Temperature & Humidity
°C
-10°CCurrent temperature from the forecast or a thermometer45°C
%
0%Humidity from the forecast or a hygrometer100%
Exposure
Quick presets
Formula & threshold sources
- 😓 Discomfort index: Korea Meteorological Administration formula (based on Thom 1959)
- 🔥 Heat index: US National Weather Service Rothfusz regression (SR 90-23)
- 📊 Thresholds: KMA discomfort index guide · NWS Heat Index Chart
- 🚑 Heat illness & first aid: Korea Disease Control and Prevention Agency
- 📋 Action guidance: Korea Ministry of the Interior and Safety heat wave guidelines
- ☀️ Full-sun adjustment: NWS (up to +15°F ≈ +8.3°C)
※ All values are reference indicators. Real perceived heat and health risk vary with individual condition, wind speed, and radiant heat.
Discomfort Index (THI)
82.1
60Comfortable 68 · Moderate 75 · High 8090
Everyone feels discomfort. Stay cool indoors and limit outdoor activity.
Heat Index & Heat Illness Risk
36.2℃
97℉ · Actual temperature 31.0℃ (Difference +5.2℃)
Extreme caution
NWS class: Extreme Caution
20℃Caution 27°C · Extreme caution 32°C · Danger 41°C · Extreme danger 54°C60℃
Heat cramps and heat exhaustion likely. Prolonged exposure may lead to heat stroke.
💧 Wet-bulb temp (approx.) 25.7℃
What to do now
- Shift outdoor activity to early morning or after sunset.
- Rest at least 10 minutes in shade or air conditioning every hour.
- Replace electrolytes with a sports drink if sweating heavily.
- Stop immediately if dizziness, nausea, or muscle cramps appear.
- Children, the elderly, and people with chronic illness should stay indoors.
Level thresholds
Discomfort Index (THI)
| THI | Level |
|---|---|
| < 68 | Comfortable |
| 68 ~ 75 | Moderate |
| 75 ~ 80 | High |
| 80 이상 | Very high |
Heat Index & Heat Illness Risk
| Heat index | Level |
|---|---|
| < 27℃ | Safe |
| 27 ~ 32℃ | Caution |
| 32 ~ 41℃ | Extreme caution |
| 41 ~ 54℃ | Danger |
| 54℃ 이상 | Extreme danger |
Discomfort index levels follow the KMA guide; heat index levels follow the US NWS Heat Index Chart.
Guide · FAQ · bal.pe.kr 도구 모음
산식·단계 기준 상세는 Guide, 자주 묻는 질문은 FAQ, 데이터 출처·운영 정보는 About 참조. 마지막 업데이트 2026-08-24. (기온 입력 허용 범위 -30~55℃)