Heat exhaustion
Move to cool. Now.
- · Heavy sweating, clammy skin
- · Weakness, dizziness, headache
- · Nausea, muscle cramps
- · Rapid, weak pulse
Get to shade or AC. Sip water. Cool your neck and wrists. Improvement should come within 30 minutes.
Heat safety
Heat is the deadliest weather event on earth.
More people die from heat every year than from hurricanes, tornadoes, and floods combined. Most of those deaths are preventable, if you know the signs and act early.
Tap a city on the map — each marker is 1 of the 10 hottest major U.S. cities from the Week of Jun 29 – Jul 5, 2026, sized by peak temperature.
Tap a city
Week of Jun 29 – Jul 5, 2026
The Heat Index — World
The 10 hottest major cities.
Week of Jun 29 – Jul 5, 2026.
- 1 of 10Jacobabad, Pakistan126°F
- 2 of 10Kuwait City, Kuwait125°F
- 3 of 10Basra, Iraq123°F
- 4 of 10Delhi, India121°F
- 5 of 10Ahvaz, Iran120°F
- 6 of 10Riyadh, Saudi Arabia118°F
- 7 of 10Baghdad, Iraq117°F
- 8 of 10Doha, Qatar115°F
- 9 of 10Cairo, Egypt112°F
- 10 of 10Marrakesh, Morocco110°F
The Heat Index — U.S.
The 10 hottest major cities.
Week of Jun 29 – Jul 5, 2026.
- 1 of 10Phoenix, AZ118°F
- 2 of 10Las Vegas, NV114°F
- 3 of 10Tucson, AZ112°F
- 4 of 10Fresno, CA110°F
- 5 of 10Sacramento, CA108°F
- 6 of 10El Paso, TX107°F
- 7 of 10Austin, TX106°F
- 8 of 10Dallas, TX105°F
- 9 of 10Oklahoma City, OK103°F
- 10 of 10Salt Lake City, UT101°F
Why it's so hot
A heat dome meets El Niño.
A widespread heat dome and a strong El Niño are driving the extreme temperatures. High pressure traps hot air like a lid over entire regions, while El Niño pushes global baselines higher, stacking record after record on top of an already warming planet.
Heat dome
A stalled ridge of high pressure that compresses and traps hot air near the surface for days or weeks.
El Niño
A warming of the tropical Pacific that lifts global temperatures and intensifies heatwaves worldwide.
Related: Excessive Heat Warning Guide
When the National Weather Service issues an Excessive Heat Warning, the heat is dangerous. Read our step-by-step action plan for what to do before, during, and after the warning.
Read the guide →Know the warning signs.
Heat stroke · 911
This is an emergency.
- · Body temp above 103°F
- · Hot, dry, red skin (no sweat)
- · Confusion, slurred speech
- · Loss of consciousness
Call 911 immediately. Do not give fluids. Cool the body any way you can while you wait.
Car safety
The 10-minute car rule.
On an 80°F day, the inside of a parked car reaches 99°F in 10 minutes. In 30 minutes, it hits 114°F. Cracking a window does almost nothing.
Never leave children, pets, or elderly people in a parked car. Not for a minute. Not with the windows cracked. Not "just to run in."
99°F
10 min
109°F
20 min
114°F
30 min
Heat map
The hottest places on earth.
A ranking that would have been unthinkable a generation ago. Every year, more cities join it.
129°F
Death Valley, USA
Regularly the hottest recorded surface temperature on earth.
159°F
Dasht-e Lut, Iran
Ground surface temperature, the hottest ever measured by satellite.
127°F
Kuwait City, Kuwait
Cars melt. Birds fall from the sky. Not hyperbole.
126°F
Jacobabad, Pakistan
One of the first major cities to exceed human survivability thresholds.
119°F
Phoenix, USA
31 consecutive days over 110°F in the summer of 2023.
121°F
Delhi, India
Home to 30+ million people during peak heatwaves.
Who the heat hurts first.
Infants + kids
Their bodies heat up 3–5× faster than adults.
Adults 65+
Sweat response weakens with age.
Pregnant people
Higher baseline core temperature.
Outdoor workers
Construction, delivery, farm, high-exposure jobs.