Weather Alerts For Grand Terrace, CA

# HEADLINE -------------------- HEAT ADVISORY REMAINS IN EFFECT FROM 10 AM THIS MORNING TO 8 PM PDT THIS EVENING # DETAILS -------------------- WHAT High temperatures in the 90s expected. WHERE San Bernardino and Riverside County Valleys-The Inland Empire. WHEN From 10 AM this morning to 8 PM PDT this evening. IMPACTS Hot temperatures may cause heat illnesses. ISSUED AT Monday, May 11, 2026 at 2:07 AM PDT ISSUED BY National Weather Service San Diego CA HEADER URGENT - WEATHER MESSAGE # PRECAUTIONARY/PREPAREDNESS ACTIONS -------------------- Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors. # AREAS AFFECTED -------------------- San Bernardino and Riverside County Valleys, The Inland Empire Including the cities of Corona, Rancho Cucamonga, Fontana, Moreno Valley, Ontario, San Bernardino, and Riverside