The heat in the soil will help germination of the seeds but water is also required but not so it's drenched. The water will actually help and aid the sun in heating the soil.
The top may look dry but check a few inches down where it counts. Same for when you water, sometimes it looks wet but it's only on the surface..especially after a long hot spell as a "waterproof crust" developes.
Also water is needed for fertilizer, it can be too harsh and will not activate properly without it.
If your lawn goes belly up don't blame me though..

Gary