Does the tournament site matter?

Not when it comes to how DFS tennis works. Yet a significant consideration is that certain players play better on certain surfaces. We would encourage you to check on players’ history at individual tournaments and their history on certain surfaces.

What about weather concerns?

It does not affect DFS tennis like other DFS sports like the NFL, NBA, or MLB. Even if a match is delayed because of weather, they will make it up because tournaments occur over several days. Tennis tournaments pretty much always finish.