Data from the European Commission's Joint Research Centre showed that there had been 53 wildfires this year, as of Thursday.

Normally by this time of year, there would have been three such fires, its data showed.

Many parts of Sweden have seen their driest weather in the May to mid-July period since records began in the 19th century, the Swedish Meteorological and Hydrological Institute (SMHI) said.

Nikos Stavrinidis had gone to his summer home in the Mati area with his wife to prepare it for his student daughter, who was coming to stay.

Before he knew it, the fire surrounded him.

"It happened very fast. The fire was in the distance, then sparks from the fire reached us. Then the fire was all around us," Mr Stavrinidis said.

There were six people in his group: Mr Stavrinidis, his wife and some of her friends.

They swam further out to escape the smoke, but as they did so, they began to be carried away by the wind and the current.

They lost sight of the shore and became disoriented.

"We couldn't see anything," he said.

Gale-force winds fanning the flames in the area also hampered firefighting efforts and whipped up the seas.

"We didn't all make it," Mr Stavrinidis said. One of the women in his group and one woman's son drowned.

"What upsets me and what I will carry in my heart is that it is terrible to see the person next to you drowning and not be able to help him. You can't. That's the only tragic thing," he said.

Mr Stavrinidis said he believed they were in the water for about two hours before being picked up by a fishing boat with an Egyptian crew.

"I'm grateful to all of them," he said.

"They jumped into the sea with their clothes still on. They made us tea and kept us warm. They were great."

© AP/Thanassis StavrakisFlames forced many people to flee into the water.

Andreaas Passios, who lives next to a compound northeast of Athens where 26 bodies were reportedly found, said "everything happened in seconds".

"I grabbed a beach towel. It saved my life. I soaked it, grabbed my wife and we ran to the sea," Mr Passios said.

Mr Passios said he and his wife stayed by the sea for two hours.

"It was unbelievable. Gas canisters were exploding. Burning pine cones were flying everywhere."

When the flames died down, Spyros Hadjiandreou came searching for loved ones.

"My niece and cousin were staying here on holiday. I don't know if they made it out," he said.

"I don't know if they are OK. I haven't heard from them."

Giannis Labropoulis from the city Patras, west of Athens, was driving along the highway when flames seemed to come out of nowhere.

He told the ABC's PM he knew there was a fire, but could not have imagined how fast it would appear.

"We were driving through the flames all of a sudden in the blink of any eye, to be honest," he said.

"We just saw the road going into smoke, and then all of a sudden the flames were on the left-hand side of the car.

"All the houses that were on the hill beside the highway, they were completely burnt out."

Mr Labropoulis said the flames came within two to three metres of his car.

"We were so kind of shocked, because although we were in an air-conditioned car, we felt the heat coming in."

"We were able to drive just I think by luck, to be honest, because the things were going on so fast, the flames expanded so fast that we could not even imagine that in three seconds this thing could happen," he said.

"The problem was that as we were driving through with all these small branches from the trees flying around, we could hear the car going, 'tak-tak-tak'.

"It felt like somebody was kind of shooting at you."