How long can I leave my 4 month old blacklab/spaniel outside?

We just got a new puppy. She's about 4 months old now. We are going to a family members place on the weekend just for the evening, but since she isn't house trained completely yet I don't want to give her the run of their house. We'd like to tie her outside, maybe bring her in periodically. How long can I leave her outside for? We will be visiting for about 5 to 6 hours. It's still a little chilly outside, but it is supposed to be 7C and sunny on friday... any answers would be appreciated. We're new to all of this! Thanks :)