Midweek rain chance for Gainesville follows a nearly rainless August

Gainesville has about an even chance of showers and thunderstorms on Wednesday, Sept. 30, according to the National Weather Service. The rain chance comes after an August in which the city recorded only about a tenth of an inch of rain, according to NWS records. The agency's Gainesville forecast, issued at 7:21 a.m. Sept. 26, gives a 50% chance to Wednesday and another 50% chance to Wednesday night.

The forecast also calls for cooler afternoons through the week. It expects a high in the low 90s on Tuesday and in the upper 80s on Wednesday. By Friday, Oct. 2, the forecast high falls to the mid-80s.

The forecast does not show whether temperatures will drop further during Friday night football. Its period ends at 6 p.m. Friday. It lists no temperatures for the games.

The rain chance follows a dry month. NWS climate records put Gainesville's August rainfall at 0.11 inch. Under 1991–2020 averages, the city normally gets close to 3 inches in August. Nearby Sherman recorded about a quarter inch, which was also far below its August normal.

The weather service office in Fort Worth named a possible second concern in its Sept. 26 regional outlook. Forecasters said a slow-moving upper-level low could raise flooding concerns toward the end of the following week. They said the details were still uncertain.

The same outlook described a change in the weather pattern. Forecasters expected temperatures early in the week to run about 10 degrees above average. After that, they expected rain and thunderstorms as temperatures moved back toward seasonal levels.

A 50% chance does not tell a rancher or a hay grower how much rain will fall. The weather service defines the figure as the chance that at least one-hundredth of an inch falls at the forecast point during the stated period. It does not forecast a rainfall total.

The cooler weather matches the calendar. NWS normals for 1991–2020 show Gainesville's average daily high falling about 10 degrees from September to October. Average overnight lows fall by about the same amount, into the mid-50s. Sherman's normals follow almost the same pattern.

For statewide context, NOAA's 2022 Texas climate assessment used observations through 2020. It reported that Texas has warmed almost 1.5 degrees since the early 1900s, and it projected more warming this century. The assessment does not explain the weather in any single week.

In Gainesville, October is normally a little wetter than September. The totals change a lot from year to year. NWS records show the city received nearly 9 inches of rain in October 2023 and a little more than a quarter inch in October 2024.