Are the sessions every 20 minutes or just on the hour?

Joy, sessions are on the hour from 6a to 8p. Excluding Sundays and Mondays.

They are on the hour

Provo Temple is every 20 mins and Provo City Center is every hour. They suggest you get there 30 mins early to make it in on time too, because they can get really full.

On the hour

Are reservations needed Friday at 2pm