It has less to do w/court surface, weather, etc than it does with team development.
The Nat'l Indoor is not an NCAA event. It's an ITA event at the beginning of the season.
The Nat'l outdoor is an NCAA event and it's the last event of the season.
That's four months of development/experience for freshmen who come in and play right away. In that 4 mo. period freshmen can work their way up the line-up, say from #6 singles to #3 singles.
And that, of course, brings up match-ups. Two teams can play each other twice but might have completely different line-ups in terms of position. The former #1 guy who lost could drop to #3 in June and win with that different match-up. The same applies to doubles. Different teams, different positions from #1 to #3.
And of course the 4 mo. season also has injuries that can scramble a line-up.
Beyond that, OSU HAS been successful outdoors. Something like 13 consecutive B1G championships and a consistent qualifier for the NCAAs. Only 16 teams made it and now that has been reduced to 8 with the new super-regional format, like baseball. Last season OSU was the #1 seed but lost in the second round.