PNW · 8-K · 20260804PR000040

Weather Impact on Demand

PINNACLE WEST CAPITAL CORP · 2026-08-04 · Importance 22 · Surprise 32

Unusually early and sustained summer heat increased electricity demand in Arizona during the second quarter of 2026. Temperatures reached 105°F in March, and residential cooling degree days rose 7% compared with the second quarter of 2025. Management said the higher usage contributed to results within expectations and supported sustained load growth.

Key facts