Here’s what the WizzAir community is saying about this exact situation (Nice → Rome flight in July):
Unlikely that a new flight will be added: Most commenters say it’s very unlikely that Wizz Air will add another flight on that route before July, even if it’s a Saturday and demand might be higher.
You can wait and see: Some users suggest you can hold off on rebooking for now, but there’s no guarantee a better time will be added and if seats sell out on the later flight you’re offered, you might lose the chance to rebook that option.
Automatic refund timing: If you don’t choose a rebooking by a few hours before the original departure, the system may automatically refund you instead of rebooking.
Wizz Air cancellation policy basics (general):
If Wizz cancels your flight, they are obliged to offer you a choice between rebooking on another Wizz Air flight subject to availability, a refund, or other options per EU rules.
Practical considerations:
If you want a specific earlier time and there’s already an available alternative that’s acceptable, rebooking now secures your seat.
If you don’t mind waiting and are comfortable risking availability, you can wait a bit, but there’s no strong indication Wizz will add flights for July.