The Gulf of Mexico and Caribbean Sea have been exceptionally quiet regarding tropical cyclone activity through late August despite moderately warmer than normal ocean surface temperatures. The primary reason for the lack of tropical cyclone activity is the dry mid-troposphere. The dryness in this region is compensation for a wet mid-troposphere across the eastern tropical Pacific and eastern half of the North Atlantic tropics.

Other than Erin, the 2025 season has been quiet so far. However, during the 2016-24 active period, after September 1 is typically quite active featuring 7 hurricanes and 3 intense hurricanes. As September 2025 approaches, the North Atlantic basin is warmer than normal but arguably the least warm since 2015. Previously, 2018 produced least warm North Atlantic basin SSTA during September when peak tropical cyclone activity occurs. However, in 2018 a weak La Nina was forming and in 2025, signs of a weak La Nina are ahead. Therefore, despite the less warm North Atlantic, the La Nina tendency should produce a favorable atmospheric environment for tropical cyclone development during SEP/OCT/NOV 2025.

Climate Impact Company offers explanation for why North America 16-30-day (week-3/week-4) temperature forecasts have routinely produced very warm bias. Unusual presence and persistence of a summertime Northeast Canada polar vortex and convection phase Madden Julian oscillation (MJO) stretched across the tropical Pacific Ocean are the culprits significantly contributing to East U.S. heat and occasional historic rainfall events.

The U.S. soil moisture observations and trend reveal ongoing and worsening West/Southwest U.S. drought and adding Northeast U.S. dryness which is (also) strengthening. The southern Canadian Prairies to the Midwest States and Carolinas are the wet zones.