Every week on tour players have different waves or times they can potentially play at. They can get any tee time from 7am to 2pm local time. Temperature can change drastically at each event throughout the day. Tour players will practice at various times throughout the week to get actual carry numbers depending on their tee time.
Paying attention to their TrackMan actual carry numbers at 6:30am when the temperature is 55 degrees will play very different at 3:30pm when the temperature has changed to 95 degrees. Knowing this information players will have two sets of numbers to prepare for, morning numbers and afternoon numbers. Coming down the stretch on Sunday afternoon carry numbers will be different than Thursday morning at 8am when there is still dew on the grass.
The hard thing to prepare for is having numbers increase during the round. Players and caddies will pay close attention to certain holes where temperatures and yardages may spike.
If you look at the examples below from the same 9 iron but hit at different times of the day, you can see how much the numbers can change. The shot order was hit at 55 degrees, 70 degrees, then 95 degrees.
7 yards of difference is nearly half a club when trying to decide where to land a ball on the green. This could be a difference between being middle of the green or in the back bunker. Tour players pay close attention to all factors especially temperate during a round. Tracking the full ball flight in any environment helps preps the world’s best players.