KEY WEST, Fla. — Diana Nyad ended her fourth attempt to swim across the Straits of Florida on Tuesday, her decades-old dream thwarted by, more than anything else, jellyfish.

Storms brewing around her and repeated jellyfish stings forced her out of the water at 12:55 a.m., her crew said.

She traveled by boat close to a rocky shoreline in Key West on Tuesday afternoon, just over 72 hours after setting out from Cuba. She made a final, short swim to a waiting crowd.

‘‘I’ve been dreaming of this crossing for 35 years now and tried it four times. And should I say that there’s no disappointment? No,’’ she said. ‘‘I’m not going to get that moment I dreamed of for so long.’’

Nyad turns 63 on Wednesday and, all told, logged 41 hours and 45 minutes of swim time. Her team acknowledged at 8 a.m. that she had to be pulled from the water, but said it had been about 20 minutes earlier, not nearly seven hours earlier, as was the case.

She also spent time out of the water during a stormy Sunday night, though that was not acknowledged until Tuesday afternoon.