Heat advisories and extreme heat warnings in effect right now, and how to stay cool
1 activeA heat advisory is the lower level and an extreme heat warning the higher level; both based on the heat index. Excessive Heat Warning is the older name for an extreme heat warning.
Heat AdvisorySan Juan and Vicinity; Northeast; Southeast; Eastern Interior; North Central; Central Interior; Ponce and Vicinity; Northwest; Western Interior; Mayaguez and Vicinity; Southwest; Culebra; Vieques; St.Thomas...St. John.. and Adjacent Islands; St CroixUntil Nov 12, 4:00 PM EST
Heat Advisory issued November 12 at 2:04AM AST until November 12 at 5:00PM AST by NWS San Juan PR
Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors. Take extra precautions when outside. Wear lightweight and loose fitting clothing. Try to limit strenuous activities to early morning or evening. Take action when you see symptoms of heat exhaustion and heat stroke.
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What to do
General steps from official sources.
Get ready
Now
The NWS advises checking in with friends and relatives who are at higher risk, especially if they do not have air conditioning.
Source: NWS: Heat Full guide →
Ride it out
During
Leaving a child, disabled person or pet locked in a car is never safe. The NWS warns that children can die in a hot car within 10 minutes.
Source: NWS: Heat Full guide →
What the heat alerts mean
A heat advisory is the lower level and an extreme heat warning the higher level; both based on the heat index. Excessive Heat Warning is the older name for an extreme heat warning.
Extreme Heat Watch
Issued when there is a potential for the heat index to reach dangerous warning levels within the next 24 to 48 hours.
Extreme Heat Warning
Issued when the heat index is expected to reach the warning level within the next 12 to 24 hours. It may be issued for lower criteria early in the season or during a multi-day heat wave.
Heat Advisory
Issued when the heat index is expected to reach the advisory range within the next 12 to 24 hours. It may also be issued for lower criteria early in the season or during a multi-day heat wave.
Example thresholds from NWS Baltimore/Washington: a Heat Advisory for a heat index of 105 to 109 east of the Blue Ridge (100 to 104 west), and an Extreme Heat Warning at 110 or higher (105 west). Source: NWS Baltimore/Washington: Watch/Warning/Advisory Definitions. Also: NWS: Heat hazard simplification (renaming of Excessive Heat products). For the full comparison across alert types, see watch vs warning vs advisory.
Key steps from our guides
Each point links to the official page it comes from.
- Do not rely on a fan as your primary cooling device. Fans do not reduce body temperature or prevent heat-related illness. Ready.gov: Extreme Heat
- If your home has no air conditioning, find a cooling center, take cool showers or baths, and drink plenty of fluids. Ready.gov: Extreme Heat
- Never leave people or pets in a closed car on a warm day. Check on family members, older adults and neighbors. Ready.gov: Extreme Heat
- Heat stroke signs include a body temperature above 103 degrees F, hot dry skin with no sweat, a rapid pulse, and confusion. Call 9-1-1 or get the person to a hospital immediately. Ready.gov: Extreme Heat
Heat alerts by state
Open a state to see its current warnings, watches and advisories.
Common questions about heat alerts
What is the difference between a heat advisory and an extreme heat warning?
Both are based on the heat index and both are issued when the heat is expected within about 12 to 24 hours. A heat advisory is the lower level and an extreme heat warning the higher one, so a warning means the heat index is expected to reach a more dangerous range. The cut-off numbers are set by each NWS office, so the same heat index can trigger an advisory in one place and a warning in another.
Is an excessive heat warning the same as an extreme heat warning?
Yes. In March 2025 the National Weather Service renamed the Excessive Heat Watch and Excessive Heat Warning to Extreme Heat Watch and Extreme Heat Warning. The Heat Advisory kept its name. The NWS said the change came from public and partner feedback and social science research, and brings the names in line with its Extreme Cold products. You may still see the old name on older web pages and in news stories.
What is the difference between an extreme heat watch and an extreme heat warning?
A watch gives earlier notice: the potential for dangerous heat within the next 24 to 48 hours. A warning means the dangerous heat is expected within the next 12 to 24 hours. Use the watch to make a plan, and treat the warning as the time to act.
What should I do when a heat advisory is in effect?
Check on older adults, children and neighbors, especially anyone without air conditioning. Never leave a child, disabled person or pet in a parked car. A fan alone does not lower body temperature, so if your home has no air conditioning, go to a cooling center or take cool showers or baths and drink plenty of fluids. Call 9-1-1 for signs of heat stroke such as a body temperature above 103 degrees F, hot dry skin with no sweat, a rapid pulse or confusion.
Do the numbers in the heat alert definitions apply everywhere?
Example thresholds from NWS Baltimore/Washington: a Heat Advisory for a heat index of 105 to 109 east of the Blue Ridge (100 to 104 west), and an Extreme Heat Warning at 110 or higher (105 west). Alert thresholds are set by each National Weather Service office, so the numbers can differ where you live. The text of the alert for your location is what applies.
Alert data comes from the National Weather Service and is refreshed every 15 minutes.