Hurricanes and Tornadoes That Hit San Sebastian, PR

The nearest NOAA station with 1991–2020 climate normals is Isabela Substn, PR RQ, 10 miles northwest of San Sebastian at 420 feet. August is the warmest, with an average high of 87°F and low of 73°F; January is the coolest, at 81°F and 67°F. May is the wettest at 7.2 inches of precipitation on average and February the driest at 2.5 inches; the year adds up to 64.0 inches over 110 days with at least a tenth of an inch. June to November, the hurricane season months, bring 58% of the year's precipitation (37.4 of 64.0 inches); the other six months are drier. September has brought the most of the 55 tropical systems that passed within 75 miles (27); a normal September there has highs of 87°F and 6.7 inches of precipitation. Highs reach 90°F on about 21 days a year, almost all from April to November. A night below freezing comes less than once a year on average. That 64.0 inches is more than at 10 of the 21 Puerto Rico stations used on this site (48%). Las Marias, 6 miles south, has its own station (Mayaguez City, PR RQ): 51.3 inches a year, 12.7 less than here, and an August average high of 90°F against 87°F.

Water temperature at the NOAA tide station Mayaguez, PR, 14 miles southwest, averaged 87°F in September and 81°F in February over 2021–2025. Sea level at the Magueyes Island tide gauge, 25 miles from San Sebastian, has risen 0.81 ± 0.06 inches per decade from 1955 to 2025, NOAA's linear trend; at that pace it is 8.1 inches in a hundred years. That is faster than at 41 of the 144 U.S. gauges with a NOAA trend.

Since 1996, the National Weather Service has logged 171 flood, rain, thunderstorm wind and lightning events that began within 10 miles of San Sebastian: 64 flash floods, 53 floods, 33 thunderstorm wind reports, 19 heavy rain events and 2 lightning strikes. They killed 4 people and injured 3, and the NWS estimated $336,000 in property and crop damage. The strongest thunderstorm gust on record here was 58 mph, on May 23, 2015. May has had the most flash floods, 21 of 64. Of the 86 Puerto Rico cities on this site with a flash flood on record, 34 have had fewer than San Sebastian.

Flood insurance policyholders in San Sebastian's ZIP code 00685 have filed 23 claims with the National Flood Insurance Program since 1998, and were paid $849,000 for buildings and contents, in the dollars of each year. 43% of the claims carry the name of a storm or flood event; the rest have no event name. Of the 72 Puerto Rico cities on this site with 10 or more claims, 14 have fewer than San Sebastian.