High atop the outer south wall of Centre Court at Wimbledon, a small rectangle has been cut away in the lush, green ivy, revealing a digital number that few, if any, of the 42,000 spectators entering the grounds each day of the tournament ever notice.
Similar to coastal warning pennants, it is a signal system — from 1 to 8 — issued from Wimbledon’s own crack meteorology department, for the tarpaulin crews to standby or rush into action. A “1” means possible showers. A “2” means the chair umpire has the discretion to halt the match. On Saturday, when the first rain drops fell on an already rain-soaked Wimbledon, the signal clicked to “4” from “3.