From the Spaceflight Meteorology Group:

The Houston/Galveston National Weather Service office has issued a Winter Weather Advisory beginning at 8PM this evening lasting through noon Friday.  As temperatures fall to near and just below freezing tonight there will be a brief opportunity for some very light freezing rain to occur. Precipitation will be tapering off in intensity and moving out right around the time freezing temperatures occur at JSC this evening. A light glaze is possible in spots particularly on elevated surfaces and bridges, signs, hand rails, etc. later tonight into the morning. Ponding of rain water tonight may freeze in spots as well. Freezing rain chances and accumulations are greater off to the west and northwest of JSC tonight.

Freezing temperatures at JSC are forecast tonight starting between 9PM and 11PM lasting until late Friday morning.