Houston woke Tuesday to mostly clear skies, temperatures near 79 degrees and humidity around 89% before sunrise. The afternoon forecast calls for a high near 95, with the heat index reaching as high as 101.
Most of the day should remain sunny, although a 20% chance of showers and thunderstorms arrives after 3 p.m. Any storm is expected to be isolated, with a locally heavier thunderstorm possible. Winds should be light in the morning before becoming southeasterly in the afternoon, with light, variable winds tonight.
Air Quality Alert covers the Houston area
An Air Quality Alert remains in effect through 7 p.m. Tuesday across the Houston, Galveston and Brazoria area. Residents can help limit emissions by sharing rides, avoiding drive-through lanes, conserving energy and keeping vehicles properly tuned.
The Air Quality Alert is a short-term pollution-reduction action and should not be confused with the region’s formal regulatory status. The Texas Commission on Environmental Quality says the EPA reclassified the six-county Houston-Galveston-Brazoria area from marginal to moderate nonattainment under the 2015 eight-hour ozone standard on Oct. 7, 2022, effective Nov. 7, 2022. That separate designation does not show whether the number of Tuesday-like alerts is rising or falling.
For the eight-hour ozone standard, TCEQ measures compliance using a three-year average of the annual fourth-highest daily maximum eight-hour concentration at monitoring sites; the average must be below 71 parts per billion, according to the agency’s ozone-attainment explanation. That technical measure describes regulatory compliance, not Tuesday’s forecast concentration.
What a heat index near 101 means
A heat index near 101 degrees is below the 103-degree level that the Harris County Public Health Heat and Health Dashboard says the National Weather Service associates with increased risk of dangerous heat-related illness during prolonged exposure or physical activity. That comparison does not mean a heat index of 101 is harmless, particularly for people spending extended periods outdoors.
The same dashboard says roads and buildings can absorb and retain more heat than rural areas, contributing to the heat-island effect. Harris County’s 2025 vulnerability assessment maps broader differences in exposure and susceptibility by combining health, environmental, social and infrastructure indicators into a ZIP-code-level Heat Vulnerability Index based on 2018–2022 data, but it is not a measurement of Tuesday’s conditions. Those limits matter: the assessment can provide local context without identifying which neighborhoods will experience a specific Tuesday afternoon’s highest heat or ozone levels.
Little relief through the weekend
Wednesday is forecast to be sunny with a high near 95 and a heat index again around 101. Highs ease to roughly 93 to 94 degrees from Thursday through Sunday, while drier air should keep heat-index readings below 100 and bring cooler nights, including a low near 76 Thursday night.
Houston’s forecast remains mostly hot and humid, with limited rain and air-quality concerns Tuesday.
