Florida Governor Jeb Bush declared a state of emergency as wildfires burned more than 25,000 acres across the state, destroying houses, forcing evacuations, and shutting down parts of Interstate 95.

Six fires have charred almost 9,000 acres on Florida’s eastern coast near Cape Canaveral, including the 6,000-acre Acera blaze in palmetto, grasses, and pines near Port St. John, and the 1,350-acre New Smyrna Beach fire 42 miles north.

While rain is forecast for much of the state today, dry weather is predicted to worsen over the next 90 days, according to Mr. Bush’s executive order, which gives him authority to allocate state resources to fight the fires.

“We are getting a bit of rain this morning, which is a good thing, but we are urging people not to get too hopeful,” a spokeswoman for New Smyrna Beach, a city of 21,000 people about 14 miles southeast of Daytona Beach, Lisa Saunders, said. “We need a significant amount of rain in order for there to be some changes.”

Florida has about 5,000 wildfires annually, mostly from March to June, according to the state’s Forestry Division. More than 2,000 fires have burned more than 27,000 acres this year, compared with about 1,300 blazes and 20,000 acres in the same period last year.

The increase is being driven by dry conditions throughout the state. Naples had its fourth-driest April ever and some areas south of Orlando have had less than half of their normal precipitation, according to the National Drought Mitigation Center’s U.S. Drought Index.

Mr. Bush and his brother, President Bush, urged residents to be cautious. The president was in Florida to speak to senior citizens about Medicare and made the comments at a fire station at the Sun City Center retirement community.

“This is one of these difficult periods for the state of Florida,” the president said in a briefing with reporters. “People need to be real careful about throwing used cigarettes out and be mindful these are dangerous conditions.”

The New Smyrna Beach fire, which was about 75% contained this morning, has destroyed three homes, forced the evacuation of about 900 residences and closed parts of I-95, Ms. Saunders said. Two firefighters were treated for smoke inhalation.

All of the evacuated residents were allowed to return home today, she said. I-95 has been reopened, though Ms. Saunders said smoke might force the road to be closed again.

Trees knocked over by tropical storms last year are keeping bulldozers from getting into position to clear ground to contain fires, and another danger is that some of Florida’s native plants let blazes spread underground, she said.

“The root balls of the palm trees and the palmettos carry the flames underground,” Ms. Saunders said. “The tree will appear healthy on the outside and the fire will actually be underneath.”

The emergency declaration allows the governor to stockpile supplies, order evacuations and activate the National Guard to provide aerial support to firefighters.