THE WEATHER BEAT · SEP 17
Three Puerto Rico rain gauges peaked on the same day, in 1975
La Parguera, Lajas and Guánica, three gauges on Puerto Rico's southwest coast, each show their wettest day on record on the same date: September 17, 1975.
Key points
- Three gauges across the southwest corner of Puerto Rico, at La Parguera, Lajas and Guánica, each show their wettest day on record falling on the same date: September 17, 1975.
- The wettest of the three, at La Parguera's Magueyes Island station, measured 13.902 inches in that single day, in a record that runs from 1959 to 2026.
- Our archive holds 64 record days on the calendar for September 17 alone; this is the biggest single-day rainfall total among them.
The day three Puerto Rico gauges maxed out together
Our house archive keeps a running tally of the hottest, coldest, wettest and snowiest day each station has ever measured. On the calendar date of September 17, three of those stations, all sitting within a few miles of each other on the southwest coast of Puerto Rico, point to the exact same day: September 17, 1975.
The biggest number belongs to Magueyes Island, the station behind our La Parguera town page. It measured 13.902 inches of rain that day, the most rain that gauge has recorded in a single day across a record that runs from 1959 to 2026. Four miles up the coast, the Lajas substation measured 12.26 inches, its own wettest day in a record stretching back to 1900. And at Ensenada, a mile inland from Guánica, the gauge read 10.299 inches, also its wettest day on file, in a record running from 1959 to 2026.
Here is where the archive stops. It records what each gauge measured and the date it happened; it does not record a cause. This desk has no NOAA or National Weather Service page in hand tonight that names what produced the rain over southwest Puerto Rico on September 17, 1975, so none is offered here. The three numbers are verified. Any explanation of the weather system behind them is not.
The Lajas gauge speaks for the most ground: it is the nearest station of record for twelve of our town pages, from Lajas itself out through San Germán, Cabo Rojo and Boquerón to El Combate at the island's southwest tip. The Guánica gauge covers five town pages nearby, including El Tumbao and Indios. La Parguera's own gauge sits close enough to town, two tenths of a mile, that it speaks only for itself.
The three gauges, for the nerds
| town | station | value | date | record span |
|---|---|---|---|---|
| La Parguera, PR | Magueyes Is, RQC00665693 | 13.902 in | September 17, 1975 | 1959 to 2026 |
| Lajas, PR | Lajas Substn, RQC00665097 | 12.26 in | September 17, 1975 | 1900 to 2026 |
| Guánica, PR | Ensenada 1 W, RQC00663532 | 10.299 in | September 17, 1975 | 1959 to 2026 |
Towns the Lajas gauge speaks for: Lajas, Maguayo, Sabana Eneas, San Germán, Betances, Monte Grande, Cabo Rojo, Boquerón, Puerto Real, Hormigueros, Pole Ojea, El Combate.
Towns the Guánica gauge speaks for: Guánica, Fuig, El Tumbao, María Antonia, Indios.
Source: the house NOAA station archive, read by beat-history.py on 2026-09-17. Every figure above is a line that tool printed. No figure here comes from anywhere else.
This is a historical summary, not emergency information. For live warnings see weather.gov and your local officials.
The rock's live forecast for the places in this story
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