Since 1987, Wimbledon has chronologically been the third Grand Slam tournament of the season.
The annual Grand Slam sequence is the Australian Open, French Open, Wimbledon and US Open. Wimbledon therefore occupies the midsummer position, usually beginning in late June or early July after the clay-court French Open and before the hard-court US Open.
The wording “since 1987” reflects a major calendar change involving the Australian Open. Before 1987, that tournament was commonly staged late in the year, so the order could look different when judged by calendar dates. From 1987 onward, the Australian Open settled into its modern January slot, making Wimbledon consistently the third major.
A common mix-up is confusing Wimbledon’s tournament number with its surface or historical age. Wimbledon is the oldest of the four Grand Slam tournaments, founded in 1877, but it is not the first major played in a modern season. It is also the only Grand Slam still played traditionally on grass.