Pope Benedict XVI will visit the Virgin of Charity of El Cobre in Santiago de Cuba on March 26. Direct flights from BWI to Havana are scheduled to begin March 21. (MARC FRANK/REUTERS)

The average high temperature at Baltimore-Washington International Marshall Airport for March 21 is 54 degrees and the average low is 35 degrees. By contrast, the average high for that date in Havana is 82 degrees and the low 67 degrees.

Comparison of the two — one giving a teasing hint of spring and the other downright balmy — has been mostly irrelevant for decades, but this year will be different.

On March 21, direct flights are scheduled to begin from BWI to the communist Caribbean island.

Approved by the White House last year, the flights are intended for those who want to make “purposeful” visits to Cuba, which is a diplomatic way of saying that going there to escape the cold, catch a tan and smoke cigars isn’t sufficient reason to satisfy a federal government that wants to maintain the appearance of an arm’s-length relationship with the politically unpalatable Cuban leadership. Travelers are subject to daily spending limits and are prohibited from bringing Cuban souvenirs or other goods home.

The charter flights are open to academics, journalists, religious institutions, cultural groups, and other organizations that can muster up a purpose other than pure tourism for the visit.

The daily 3 p.m. charter flights are being provided by a company called Island Travel & Tours, which began selling tickets on Tuesday. The first flight is scheduled for four days before Pope Benedict XVI’s planned visit to Cuba from March 26 to 28.

“What could be better than to have these flights coincide with the papal visit?” said William Hauf, president of Island Travel & Tours.