Hamilton took pole for the race - his first at Interlagos - and has never taken victory in Brazil.
"I think the weather is going to be tricky tomorrow so will definitely make it more of a lottery", he said.
"We have put ourselves in a really good position and we will do best job we can as a team. It's the best we have been for quite some time, so we will do everything we can to get a top result".
Hamilton also indicated that McLaren has not set-up for a wet race.
"We have just set the car up to attack for qualifying. We don't know what the hell is going to happen tomorrow. We have to make sure we get our tyre temperatures right, and try and steer clear of any big puddles".