Heat Stress Index (Core Feature, Included)

The Heat Stress Index helps monitor discomfort and potential health risks caused by high heat and humidity. Based on the Ezra Zohar formula, this index calculates heat stress by combining air temperature and humidity, offering real-time, categorized insights into environmental heat exposure.

🌐 This feature is part of Tomorrow.io’s core (free) offering and is available to all platform users.

Calculation Method

The Heat Stress Index (also known as the Discomfort Index) is derived from:

• Dry Bulb Temperature – Standard air temperature
• Wet Bulb Temperature – A humidity-influenced temperature that reflects evaporative cooling

The combined result categorizes heat stress into six severity levels:

Accessing Heat Stress Index on the Platform

This feature is available to all users with platform access.

To view the Heat Stress Index:

1. Log into your Tomorrow.io account
2. Navigate to Map View
3. Toggle on the Heat Stress Index layer from the layer menu
4. Optionally, view historical or forecast data in the Trends tab by adding the parameter

API Access

The Heat Stress Index is available via the Tomorrow.io API. Developers can:

• Retrieve real-time and forecasted index values
• Use the API assistant for guided query setup
• Refer to the API Documentation for additional support

Need Help?

For questions or support using the Heat Stress Index, contact your Account Team or email support@tomorrow.io.