# United States extreme heat wave

> Live situation record from CLSTR: https://clstr.news/situations/united-states-extreme-heat-wave
> Updated: 2026-09-04T20:35:49.000Z. Sources: 71. Developments: 2.

A severe late-summer heat wave has impacted large portions of the United States, affecting over 100 million people under various heat advisories. The National Weather Service reported critical conditions in the Midwest, the southern plains, and the Mississippi Valley, with heat index values expected to reach or exceed 40.5 degrees Celsius (105 degrees Fahrenheit).

As the heat wave intensified through the Labor Day weekend, concerns grew regarding the health and economic impacts of the extreme temperatures. In New York City, advocates noted that extreme heat serves as the city’s ‘deadliest climate threat,’ disproportionately affecting marginalized communities by increasing utility costs and straining those with pre-existing medical conditions. The period of unrelenting heat was expected to persist until a midweek cold front arrived.

## Timeline

### 2026-09-04: Heat wave intensifies across United States during Labor Day weekend

A major heat wave is affecting the central and southern United States during Labor Day, while experts warn that extreme heat in New York City is exacerbating health and economic inequalities.

4 sources. https://clstr.news/cluster/heat-wave-intensifies-across-united-states-during-labor-day-weekend

### 2026-08-31: United States heat wave affects over 100 million people

Over 100 million people in the US are under heat advisories, with 46.7 million facing extreme heat across the Midwest and South as temperatures reach critical levels.

67 sources. https://clstr.news/cluster/soutomaior-and-zafra-forecast-sunny-warm-weather

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Cite as: United States extreme heat wave. CLSTR, https://clstr.news/situations/united-states-extreme-heat-wave