At least 32 deaths have been reported in Florida and seven more combined in Georgia and SC.
The eight elderly patients who died at a Broward County nursing home have not yet been included in the death toll.
The greatest number of outages were reported in Glynn County on the coast and Dekalb County in the central part of the state.
More than 60,000 workers from across the United States and Canada were involved in the restoration efforts, including those from the affected companies and other utilities, according to the Edison Electric Institute, an industry trade group. That number is almost a million fewer than Thursday morning.
Some 5.8 million homes and businesses in Florida and nearby states still had no power on Tuesday after the pummeling from Hurricane Irma, as utility companies scrambled to get the lights back on in one of the biggest power restoration efforts in USA history.
FPL, the state's largest utility, said its outages dropped to around 1.9 million customers on Wednesday from a peak of more than 3.6 million on Monday.
While power has been restored to many since the disaster, a few customers may be without electricity for weeks before the utilities fix the most damaged parts of the system, Reuters reports.
In Sarasota County, 23 percent of customers - 59,600 FPL customers and four cooperative customers - were waiting for power to be restored as of 9 a.m. "We will not stop until 100 percent of Florida homes and businesses have power so all families can get back to their normal lives".
Georgia Power said it believes 95 percent of impacted customers will see service restored by Sunday night.
The state says it is working to restore power to assisted living facilities and nursing homes in the impacted areas. He held calls with utility companies and directed the Florida Highway Patrol (FHP) to provide law enforcement escorts to utility vehicles to ensure that they can quickly and safely reach communities still in need.