Johnson Lake Weather Forecast
- 77
- 98
Hot
- 76
- 97
Hot
- 75
- 96
Mostly Sunny
- 74
- 96
Mostly Sunny
- 75
- 95
Partly Sunny
- 74
- 95
Slight Chance Thunderstorms
Today 12 Sep Washington
Mostly sunny. A slight chance of Showers and Thunderstorms this afternoon. Hot with Highs in the upper 90s. South Winds 5 to 10 Mph. Chance of rain 20 percent. Heat index Values up to 107.
Tonight 12 Sep Washington
Mostly clear. A slight chance of Showers and Thunderstorms in the evening. Humid with Lows in the upper 70s. South Winds 5 to 10 Mph. Chance of rain 20 percent. Heat index Values up to 105 early in the evening.
Johnson Lake Temperature Statistics
September Temperature
Brenham, Brenham Municipal Airport (6.2 miles)
Lowest 5 September, 2026
74.3 °FAverage September
83.3 °FHighest 2 September, 2026
100 °F
Climate (2021–2026)
Brenham, Brenham Municipal Airport (6.2 miles)
Average Low 2021–2026
60.9 °FAverage 2021–2026
70.8 °FAverage High 2021–2026
81.7 °F