Hottest Week of Summer 2025
07/27/2025, 11:42 am EDT
Testing Warm ECM Vs. Colder AI for Brazil Ahead
07/29/2025, 5:29 am EDT
Climate Impact Company U.S. Medium Range Report
Issued: Monday July 28, 2025
Highlight: Cool break is brief.
Chart of the day: Latest U.S. population weight CDD outlook.
Discussion: The U.S. population weight CDD forecast utilizing all models into mid-August reveals this week’s heat spike, the hottest of summer, followed by a major cooldown for early August, and regenerating heat into mid-August.
Medium-range 6-10 Day Forecast Valid August 2-6, 2025
Discussion: The U.S. shifts cooler in the 6-10-day period including much of the East and Northwest States. The 4-Corners/Texas region is hot. Lingering wet weather in the Southeast due to the cooler pattern change while the Canadian Prairies to the North-central U.S. are wet.
Medium-range 11-15 Day Forecast Valid August 7-11, 2025
Discussion: A warmer change as ECM ENS loses the cool regime and rewarms much of the U.S. including hot weather extending from California to the Mid-south States. Note the wet arc across Cuba possibly related to a tropical system.
U.S. Medium-range Temperature Forecast Using AIFS ENS
Discussion: The AIFS ENS is slightly cooler than ECM ENS in the 6-10-day period followed by a warm-up less bold than indicated by ECM ENS.
Days 16-20 Extended range Temperature Forecast valid August 12-16, 2025
Discussion: In the extended range, the Northwest/Interior West and Northeast are hot. The tropics should be percolating.