San Antonio is starting Tuesday, August 4, 2026, under mostly clear skies, but the heat will build quickly. Afternoon temperatures are expected to reach 99 degrees, with heat index values as high as 107.
Afternoon Heat Peaks Near 100
By late afternoon Tuesday, southeast winds of 5 to 10 mph will offer only limited relief as temperatures climb toward the upper 90s. According to the National Weather Service, the forecast report lists no active watches or warnings for the area.
Tuesday night will stay mostly clear, with a low near 78 degrees, but the heat index could remain as high as 103. Winds from the south-southeast may gust up to 25 mph overnight, so outdoor plans should account for both the heat and occasional stronger breezes.
Mostly Dry Through The Weekend
Wednesday, August 5, is expected to be another mostly sunny day with a high near 98 and a heat index near 105. Highs should remain near 98 Thursday, 97 Friday, 96 Saturday and 95 Sunday before returning to about 97 Monday.
Rain chances in San Antonio stay in the single digits through Monday. The main exception is a low chance of sea-breeze showers or storms late in the week across the southeastern Coastal Plains, while inland areas around San Antonio are expected to remain mostly rain-free.
Warm Nights Bring Little Relief
Overnight lows will hover around 77 to 78 degrees through Monday, keeping homes, pavement and bodies from fully cooling down. The National Weather Service also expects some haziness or a milky-looking sky through Wednesday from suspended smoke particles and a light plume of Saharan dust.
Residents should schedule strenuous outdoor work for the cooler parts of the day, drink water regularly and take breaks in shade or air conditioning. During a Level II heat advisory last week, San Antonio Metro Health advised residents to check on older adults, children and people with special needs, guidance that remains relevant as the hot stretch continues.
