Print Card
Print Card — Opens a clean, high-contrast 4×6 layout ready to laminate.
Your Personal Heat Danger Temperature in 15 Seconds
Heat advisory issued? Enter your profile — get a specific wet-bulb stop temperature and a printable action card for the fridge.
Your Personal Heat Protocol
One card. Three steps. Tape it to the fridge.
Save Image
Save Image — Downloads a PNG of your card for phone or caregiver group chat.
Share for a Loved One
Share Link — Sends a pre-filled calculator so family gets their own card instantly.
How It's Calculated
WBGT Formula
We use the Liljegren et al. (2008) simplified WBGT approximation for shade conditions: WBGT = 0.567×Ta + 0.393×e + 3.94, where Ta is air temperature (°C) and e is vapor pressure (hPa) derived from relative humidity. This formula is validated for outdoor shade with no wind or globe temperature measurement.
Thresholds by Profile
Base danger threshold: 28°C WBGT (82°F) for a healthy adult doing moderate work (ACSM/NIOSH). Modifiers applied: Age > 65 adds +2°C; each checked health condition adds +2°C; heavy activity adds +2°C; moderate activity adds +1°C; light/resting adds 0°C. Your personal threshold = base + sum of modifiers.
Data Sources
Liljegren et al. 2008, J. Occup. Environ. Hyg. 5(10):645–55. ACSM Position Stand 2007, Exertional Heat Illness. NIOSH Criteria Document 2016, Occupational Exposure to Heat. All links open in new tabs.
Privacy
No data is stored or transmitted. All calculations run in your browser. Geolocation is used once to fetch current humidity from Open-Meteo (no API key) and is never saved. The share link encodes your inputs in the URL hash only.