In September high temperatures begin to fall, but not too much. Humidity also decreases. Thunderstorms still take place, especially in northern and western parts of Texas. There can be more rainy days. But Southern part remains dry. If you feel like swimming in the ocean, September is a good time as water is the warmest during this month.
October still feels as warm as summer. Light rains occur along with thunderstorms. Around 30-35% of the days are rainy almost on the whole territory except eastern part known for clear sky. In November temperatures continue falling. In the north, night temperatures can even fall to -2 °C. It begins to snow in northern and western parts of Texas. A little snow can appear in the central part. Rain is mostly moderate and light.