Houston is waking up to another steamy start, with clear skies, temperatures parked near 75°F and dew points in the mid-70s that make the air feel downright soupy. The heat will ramp up fast, with the thermometer expected to push into the upper 90s to around 100°F this afternoon, and only a light breeze to stir the air. A Heat Advisory is in effect Tuesday, July 21, and the most dangerous heat will arrive from midday through the afternoon.
Afternoon Heat And Safety
The National Weather Service has posted a Heat Advisory for Tuesday, July 21, from 11 a.m. to 8 p.m. CDT, calling for highs near 100°F and heat-index values that could reach 106–108°F. Those numbers are not just uncomfortable, they raise the risk of heat-related illness. Limit long stretches of outdoor activity, drink plenty of water, and keep an eye on older neighbors and anyone without air conditioning. For the full advisory text and the latest updates, see NWS Houston/Galveston.
Timing And Commute
Morning commuters will deal with muggy but quiet weather and light west winds. The real punch comes later, when sidewalks, transit stops and parked cars turn into hot plates during the mid- to late-afternoon rush. Overnight will not offer much of a cooldown, with lows only dipping to around 80°F Tuesday night, so the heat lingers well after sunset. For anyone needing a break, city libraries and community centers serve as cooling sites, and the Houston Health Department provides locations and 3-1-1 guidance.
Late Week Bertha Watch
Forecasters are also keeping an eye on Tropical Storm Bertha for potential late-week effects. Current models suggest the storm may weaken as it tracks west across the northern Gulf, but outer bands could still throw showers and breezy weather at the region from late Friday into the weekend. Coastal spots would feel any changes first if Bertha trends farther west, so outdoor plans along the shore may need some wiggle room. Local forecasts will refine the timing and potential impacts as the week goes on.
Bottom line, try to avoid strenuous outdoor work from late morning through early evening on Tuesday, and again on Wednesday if the heat holds on. Hydrate frequently, use cooling centers or air-conditioned breaks when you can, and employers or event organizers should push the heaviest tasks into the early morning or evening while the advisory is active.
