http://www.houstonpress.com/news/bundle-up-an-arctic-blast-is-forecast-for-houston-8795496

The Houston/Galveston office of the National Weather Service is predicting the first cold front of the fall, which will move into Harris County from the west by Sunday evening and may bring more than two inches of rain. 

Temperatures may drop to a frigid 65 degrees by Tuesday night (better bring those delicate plants inside). And the highs may only reach the nippy mid-80s during the early part of the week. KHOU forecasters predict temperatures 10-20 degrees below normal for the middle of next week — no way to survive that without a pumpkin spice latte (I guess PSL is what the kids call them now?).

The weather service forecasters are conservative in their predictions, but others are more bullish. The Space City Weather Blog gives a 50 percent chance temperatures will drop to the practically-below-freezing high 50s Tuesday and Wednesday evening.