The snakes are still hibernating here in SE AZ. We don't normally start seeing them until about the end of March though a warm spring can have them out earlier.

I highly recommend giving any outdoor dog rattlesnake aversion training. My last, late, Malamute and my present Golden Retriever were both snake trained and both avoided/avoid rattlers like they were the plague. The alternative is a potential vet bill of about $3500 for antivenin treatments. At least that is what it cost my neighbor when his Rottweiler was bitten.