Severe Weather near Philadelphia
This alert is in force until 1 September 2026, 20:00 UTC.
It is the 264th strongest of the 387 detections recorded within 20 km of this point since 12 March 2026. The last comparable one was on 28 August 2026.
What the source measured
HEAT GOV reported: * WHAT...Heat index values up to 100 degrees expected. * WHERE...In Delaware, New Castle County. In New Jersey, Mercer, Camden, Gloucester, and Northwestern Burlington Counties. In Pennsylvania, Delaware, Eastern Chester, Eastern Montgomery, Lower Bucks, and Philadelphia Counties. * WHEN...From...
An estimated 3,686,169 people live within 50 km of this point.
Nearby, since 12 March 2026
- July 11, 2026 · score 52 · 1.7 km
- July 6, 2026 · score 52 · 3.3 km
- March 17, 2026 · score 52 · 3.5 km
How we know
One source: HEAT GOV. Not yet confirmed by a second, independent source.
Our own score for this event is 46 out of 100, at 69 % confidence.
The score is ours, computed from intensity, exposed population and local history — not the source’s.
Event Data
| Type | Severe weather |
| Severity | medium |
| Calamity Score (ours) | 46 / 100 |
| Our confidence | 69% |
| Coordinates | 39.9492, -75.1543 |
| Nearest City | Philadelphia (0 km) |
| Population Exposed | 3.7M within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-09-01T16:00:00.000Z |
| Source | http://www.weather.gov |
Score Breakdown
Technical Details
| Event | Heat Advisory |
| Urgency | Expected |
| Certainty | Likely |
| Onset | 2026-09-01T12:00:00-04:00 |
| Expires | 2026-09-01T16:00:00-04:00 |
| AreaDesc | New Castle; Mercer; Gloucester; Camden; Northwestern Burlington; Delaware; Philadelphia; Eastern Chester; Eastern Montgomery; Lower Bucks |
| SenderName | NWS Mount Holly NJ |
| ZonesUsedForCentroid | 10 |
| ZoneCount | 10 |
Safety Information
Always follow official guidance from your local emergency management agency. This platform provides scientific monitoring data and is not a substitute for official warnings. If you are in immediate danger, contact your local emergency number.
Series begins 10 February 2026. Comparisons refer to that period only. Collection gap: 14-26 August 2026.
This data is aggregated algorithmically from scientific sources. Not a replacement for official emergency warnings.
Want to know when something happens near Philadelphia?
Calamity.live data shows a weather event with CalamityScore 46/100, near Philadelphia (United States), based on data from heat_gov. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.