Tropical Cyclone Sinlaku put on a spectacular display of rapid intensification over the warm Pacific waters southeast of Guam early Sunday, becoming the world’s second Category 5 tropical cyclone of 2026 at 11 a.m. EDT April 12, with 175 mph (280 km/h) winds, as rated by the Joint Typhoon Warning Center (JTWC). Sinlaku will pose an extremely dangerous threat to the U.S. Northern Mariana Islands on Monday and Tuesday.
Sinlaku likely peaked at 5 p.m. EDT Sunday, with 180 mph (285 km/hr) winds. Sinlaku is very close to its maximum potential intensity (MPI) — the greatest intensity that a tropical cyclone can reach under the existing atmospheric and oceanic conditions — which should be close to 175 mph (280 km/hr), according to a graphic from the University of Wisconsin CIMSS (see Bluesky post below).
At 21Z Sunday, the Japan Meteorological Agency, the official agency responsible for typhoon warnings in the Northwest Pacific, estimated that Sinlaku’s central pressure was 905 MB, with 135 mph (215 km/h) winds (10-minute average, which is normally substantially lower than the 1-minute average used by the Joint Typhoon Warning Center). Sinlaku’s name was contributed by the Federated States of Micronesia and refers to the goddess of nature and breadfruit of Kosrae Island.
Sinlaku took advantage of favorable conditions for its rapid intensification: low wind shear of 5-10 knots, sea surface temperatures of 28-29 degrees Celsius (82-84°F), with warm waters that extended to great depth (an ocean heat content of 125-150 kilojoules per square centimeter). Sinlaku intensified by 75 mph (120 km/hr) in the 24 hours ending at 12Z Sunday. The Joint Typhoon Warning Center is predicting that Sinlaku has peaked in intensity and will slowly weaken on Monday as it approaches the U.S. Northern Mariana Islands, and pass very near the islands of Tinian (population 2,000) and Saipan (population 43,000) on Tuesday morning (U.S. EDT).
A historic storm for so early in the year
The list of category 5 typhoons classified by JTWC for the months of January–April is a short one, with just ten storms:
Surigae, 195 mph winds, Apr. 17, 2021;
Hester, 185 mph winds, Jan. 1, 1953;
Sinlaku, 180 mph winds, Apr. 12, 2026;
Maysak, 175 mph winds, Mar. 31, 2015;
Thelma, 175 mph winds, Apr. 20, 1956;
Wutip, 165 mph winds, Feb. 23, 2019;
Isa, 165 mph winds, Apr. 20, 1997;
Mitag, 160 mph winds, Mar. 5, 2002;
Andy, 160 mph winds, Apr. 21, 1989; and
Ophelia, 160 mph winds, Jan. 13, 1958.
Two Cat 5s so far in 2026
The other Cat 5 of 2026 so far has been Tropical Cyclone Horacio, which peaked with 160 mph (260 km/h) winds over the warm waters of the remote South Indian Ocean on Feb. 23, 2026. Horacio did not impact any land areas. The 1990-2025 average yearly number of Category 5 storms globally was 5.3; there were five in 2025 (Hurricanes Melissa, Erin, and Humberto in the Atlantic; Typhoon Ragasa in the Northwest Pacific; and Cyclone Errol in the South Indian).
As seen in Fig. 1, there has been an increase in the number of Cat 5s globally since accurate global satellite data became available in 1982 (technically, this is statistically significant at the 99.5% level). Climate change is expected to increase the proportion of tropical cyclones that reach Category 4 and 5 strength.
Bob Henson contributed to this post.
Republish our articles for free, online or in print, under a Creative Commons license.
