HAVANA — Old computer processors whirred and paint crumbled from the walls in the National Prognostic Center of Cuba’s Meteorological Institute, set on a rise above Havana’s old city. Half a dozen meteorologists shifted their gaze between satellite images on large video screens and a giant overhead map of the United States.

They monitor the region’s weather every day, but their gaze grows especially intense in hurricane season. As the center’s director, José Rubiera, explained, almost every hurricane that strikes the Southern United States passes through Cuba first. “A hurricane that hits Cuba doesn’t ask for a visa before entering the United States,” he said.

This shared destiny has led to a rare truce between the two nations, which have had no bilateral relations for more than 50 years. Their meteorological agencies exchange satellite data, jointly analyze radar and collaborate on storm forecasting.

When a storm is approaching, “we call the National Prognostic Center or they call us, whoever gets to the phone first,” said Lixion Avila, a senior specialist at the United States government’s National Hurricane Center.