The latest Climate Impact Company U.S. cooling degree day assessment for summer 2026 given the recent decline in natural gas prices. Regenerating important warmth is likely for later summer while hotter operational models continue to battle cooler AI forecasts in the extended range.

The North Atlantic basin has warmed 0.34C during the past 30 days to +0.70C, a (fairly) warm signature. However, the main development region is almost exactly normal and has cooled slightly in July so far. The Caribbean Sea warmed to +0.53C although all of the surface warming in in the northwest basin. The Gulf of Mexico is warming rapidly reaching +1.10C. The western North Atlantic basin has (also) warmed to +1.10C.

The estimated U.S. CDD forecast for week 3-5 ahead remains hot according to ECM while AI models are consistently much cooler. Interestingly, CFS V2 is sharply cooler for week-3 then bounces hotter for week-4/week-5. The primary issue is whether the East U.S. is hot (or not). The East cools off later July but should gradually reheat although not as aggressively as ECM. CFS V2 has the right “trend” and AI models are too cool.

During late June/early July, emergence of a strong positive phase global atmospheric angular momentum (++GLAAM) regime has returned. The new surge of +GLAAM is related to the onset of an El Nino climate. Previously, a pulse of ++GLAAM was observed during late May/early June, elated to a strong Madden Julian oscillation (MJO) episode, and the correlating U.S. temperature anomalies were extremely warm, especially for the Central U.S.