Google displays excessive heat warnings when:
- The combination of temperature and humidity is considered dangerous for the human body (according to the NWS Heat Index danger threshold).
- Heat is above normal for that location in comparison to previous years.
- Excessive heat conditions lasts for at least 2 consecutive days.
They also provide:
Insights and relevant weather information like:
- The current temperature.
- How hot it actually feels.
- How long the excessive heat might last.
- Weather forecast information.
- Safety tips from the Global Heat Health Information Network.
Important: Excessive heat warnings are approximate and for informational purposes only. Check official sources for more information.