Grid Stress Has Two Seasons

Electrical-grid stress in Harris County has two seasons: winter cold early each year and sustained heat during summer. A review of 486 NOAA/NWS Storm Events reports from April 2017 through April 2026 shows why households should prepare for both, though the underlying hazards look different.

Winter weather appears only 15 times, about 3 percent of the record, but it accounts for 41 deaths. Nearly all occurred during the February 2021 freeze. Cold can drive heating demand higher while disabling power generation, fuel delivery, and equipment at the same time. A rare event can produce severe consequences.

Heat is more frequent and persistent. The report identifies heat activity from June through September, including ten hot weeks in 2023 associated with 12 deaths. High temperatures increase air-conditioning demand and can reduce the carrying efficiency of transmission and distribution lines, narrowing the system's operating margin when equipment fails.

These two peaks create a practical preparedness calendar. Before January, homeowners should test batteries, generators, carbon-monoxide alarms, weatherization, and a safe plan for maintaining one warm room. Before June, they should identify the circuits needed for refrigeration, communications, medical devices, fans, or efficient cooling, then estimate how long backup power can support those loads.

The broader storm record adds another warning. Wind and lightning make up 188 reports, and the strongest gusts can damage poles and local distribution equipment. Spring storms may cause outages even outside the two demand-stress seasons, so routine maintenance and backup testing still matter year-round.

NOAA reports describe weather events, not actual ERCOT operating conditions, outage counts, customers affected, or restoration time. The grid-stress connection is therefore a planning inference, not a measured outage result. Even so, the seasonal pattern is useful: prepare twice, once before winter and again before summer, while keeping essential-load plans ready for severe storms in between.