DUK · 8-K · 20260804PR000037

Weather Impact on Demand

Duke Energy CORP · 2026-08-04 · Importance 30 · Surprise 32

Weather conditions varied materially across Duke Energy’s U.S. service territories during the three and six months ended June 30, 2026. Duke Energy Progress reported six-month heating degree days up 3.8% year over year and cooling degree days down 4.9%, while Duke Energy Carolinas reported six-month cooling degree days up 3.8% and heating degree days down 1.8%. Duke Energy Florida’s six-month heating degree days increased 15.9%, and its unbilled sales increased 41.0% to 726 GWh, indicating a significant weather-related demand and billing effect.