At what temperature should I call it a night ?Is it still to early I really want to hunt this weekend but I know the temps drop really fast this time of year.

Not necessarily too early...what's the earliest an alterna has been observed?

Temps have been squirrely this year for much of the country; don't know about W TX specifically. I say go for it, and record all climatic conditions even if no snakes are found. It's important to have that data as well as that for successful nights.
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Chris McMartin
www.mcmartinville.com
I'm Not a Herpetologist, but I Play One on the Internet