Weekly natural gas cash prices rallied for a third straight time, propelled by record heat and surging cooling demand.

NGI’s Weekly Spot Gas National Avg. for the July 24-28 period jumped 26.5 cents to $2.885, despite a late week selloff following a force majeure in West Texas and ahead of an expected reprieve from toasty temperatures in the Northeast.

Weather conditions during the week were the epitome of bullish, with high temperatures in the California deserts and the Southwest persistently topping 100 – often above 110. A record July heat wave baked Phoenix and other markets. Texas remained extremely hot as well, and lofty temperatures also spread through the Midwest and to the East, driving robust national consumption.

“The heat is driving impressive demand,”...