No, the physics of the ionosphere do not reset with our clocks, unfortunately.
Stations with PSA pre-sunrise authorization may sign-on at greatly reduced power.
But true daytimers will have to wait the extra hour for sign-on.
The FCC has standards for determining whether a station may have PSA authority.
Generally the class of station, location, whether or not it's in a protected border zone, etc.
are all factors they take into consideration.
A station like WEDO for example does not qualify as it must protect WGY on a clear channel.
In some cases the PSA power authorized is as little as 1 to 5 watts, which makes me wonder
why they even bother.
On the plus side come Sunday I'll be able to pull out one of my collectable AM radios and spend
evenings on the back porch with a cold beverage listening to music on 620 KHB.