Eight tropical storms formed in the eastern North Pacific in September, and seven of them strengthened into hurricanes. Five of those reached major hurricane intensity, meaning Category 3 or stronger, with sustained winds of at least 111 mph. According to NOAA’s September global climate report, the hurricane count and the major hurricane count were both records for the month in that basin, while the eight storms tied the September record for named systems.
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The tally came out on Oct. 9, and it describes a basin that spent the month working through one powerful storm after another while the Atlantic, as a separate story from the same bulletin shows, went the month without a single hurricane.
Record September counts in the eastern North Pacific
Meteored’s summary of the NOAA report lays out the basin’s September in four numbers: eight tropical storms, seven hurricanes, five major hurricanes, and records set for both of the latter. A second account of the same bulletin, from Business Today, gives identical figures and adds the global picture: 19 tropical storms formed worldwide in September, and the eastern Pacific supplied 8 of them.
Scale matters here. The Climate Prediction Center’s seasonal outlook, issued in May, gave a 70 percent chance of an above-normal eastern Pacific season and a likely range of 5 to 9 major hurricanes for the entire season, against a 1991-2020 average of four. One month of activity therefore equaled the low end of the forecast range for the whole season. The same outlook put the odds of El Niño during the season at 96 percent, and it said no further updates would follow.
September also followed a busy summer. By the end of August the basin had already produced Hurricane Genevieve, a Category 5 storm with peak winds of 160 mph between July 24 and Aug. 2, which Wikipedia’s running season page describes as the first Category 5 in the basin since Kristy in 2024, along with Category 4 Hurricane Lala, which passed just south of the Big Island of Hawaii. The record September therefore built on a season that was already running hot, rather than arriving from nowhere.
El Niño and the warm water beneath it
NOAA attributed much of the exceptional warmth across the tropical Pacific to persistent El Niño conditions, and the Climate Prediction Center said on Oct. 8 that El Niño is continuing to strengthen, with a strong-to-very-strong event likely through January-March 2027, as the Business Today report relays. Global ocean surface temperatures averaged 1.10 degrees Celsius above the historical average in September, a record for any month and the fourth monthly record in a row. Meteored’s account says the central and eastern tropical Pacific were among the warmest regions.
The ocean data go further back than the October bulletin. A September 15 review of the season cites the Climate Prediction Center’s Sept. 10 discussion: the Nino-3.4 index reached plus 1.8 degrees Celsius in August, eastern equatorial Pacific temperature anomalies exceeded plus 3.0 degrees, and forecasters saw better than a 90 percent chance of a very strong event. That review also reported 15 named storms and six hurricanes in the northeast Pacific as of Sept. 3, already well above normal.
Norbert, Polo and Lowell: the storms inside the count
The September run did not look inevitable from the middle of the month. On Sept. 13, FOX Weather’s Bryan Norcross wrote that “At least for a while, the Eastern Pacific seems to be calming down,” with Tropical Storm Norbert fading near Hawaii and the next two names in line, Odalys and Polo, expected to meet hostile winds, according to his Sept. 13 analysis.
Polo broke that expectation. The Associated Press reported on Sept. 22 that Hurricane Polo had grown into a Category 4 storm off Mexico’s Pacific coast, was expected to reach Category 5 strength, and was forecast to pass near the southwestern coast of the country. Polo is one of the September storms that fed the major hurricane count, though the NOAA summaries read for this article do not list which five systems made it.
Hawaii felt the season more directly. NOAA’s national climate report for September credits Hurricane Lowell with contributing to the state’s second-wettest September in a 36-year record: 10.83 inches of precipitation, 6.42 inches above the 1991-2020 average. Year-to-date rainfall across the islands stood at 86.66 inches, making January through September the wettest such stretch on record.
The basin’s season officially runs from May 15 to Nov. 30, according to the Climate Prediction Center, so two months remain on the calendar. What the record cannot yet say is how September will rank once the full season is tallied, and whether the strong-to-very-strong El Niño the Climate Prediction Center expects through early 2027 keeps the Pacific this productive into the fall.
This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.
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