Come Wednesday morning, and parks across the world will be full of Jews performing an unusual ritual: the blessing over the Sun, which is said only once every 28 years. A number of ceremonies are being planned here to celebrate the mitzvah but the weather forecast is looking distinctly unfriendly. In 1953, when the outlook was soggy, the American Airforce offered parachute training to a squadron of rabbis so they could recite the berachah as they dropped through the sky above the rain clouds. If the Chief Rabbi is unable to call in the RAF, perhaps someone can erect a giant sunlamp in Trafalgar Square.