Right now
The most recent data we hold from HEAT GOV arrived 6 hours ago, and this point is in it.
One other detection within 20 km in the last 24 hours, <1 km from here.
This alert is in force until 21 September 2026, 19:00 UTC.
No stronger detection stands among the 19 recorded within 20 km of this point since 28 April 2026 — 10 others scored the same. The last comparable one was on 20 September 2026. 6 more were recorded here in the fortnight before it.
What the source measured
HEAT GOV reported: * WHAT...This level of heat affects most individuals sensitive to heat, especially those without effective cooling and/or adequate hydration. * WHERE...All of Puerto Rico, including Vieques and Culebra, and the U.S. Virgin Islands. * WHEN...From 10 AM this morning to 3 PM AST this afternoon. ...
Urban PEI: 1,338,231 within a heuristic 50 km radius; not unique people.
Nearby, since 28 April 2026
- September 19, 2026 · score 46 · 0.0 km
- September 12, 2026 · score 46 · 0.0 km
- September 8, 2026 · score 46 · 0.0 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.
This is our versioned heuristic index, not source severity or a calibrated probability. Urban PEI does not count unique people.
Computed under scoring rules v5. Rows carrying other versions were judged by different rules and are not directly comparable.
Event Data
| Type | Severe Weather |
| Severity | Medium |
| Calamity Score (ours) | 46 / 100 |
| Legacy data-support index | 0.70/1 |
| Coordinates | 18.0799, -66.1773 |
| Nearest City | Cayey (3 km) |
| Urban exposure index (PEI) | 1.3M within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-09-21T14:00:00.000Z |
| Source | http://www.weather.gov |
Physical priority index · v5. Heuristic priority, not calibrated probability, predictive accuracy or damage. The legacy data-support index combines assigned source support and field availability. Urban PEI is distance-weighted and does not count unique people; zero does not establish that nobody is present. Model cards.
Source and revision timeline
Source: heat_gov. Occurrence: 2026-09-21T14:00:00.000Z.
First archived: 2026-09-21T06:08:54.721Z. Material modification: not recorded.
Retained revisions are prospective; earlier versions may be unavailable. No revision entry does not prove that a record never changed.
Score Breakdown
Technical Details
| Event | Heat Advisory |
| Urgency | Expected |
| Certainty | Likely |
| Onset | 2026-09-21T10:00:00-04:00 |
| Expires | 2026-09-21T15:00:00-04:00 |
| AreaDesc | San 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 Croix |
| SenderName | NWS San Juan PR |
| ZonesUsedForCentroid | 8 |
| ZoneCount | 15 |
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 8 March 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.
Review the area, threshold and delivery channel in your account.
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