When the All England Club threw its gates open on Friday, a booming voice through the PA system welcomed the spectators flocking into the grounds with the words "there is an increasing risk of heavy thundery showers as we move through the day".
The news was greeted with glee by many of the 15,000 Centre Court ticket holders, who hoped to become the first to see a competitive match under the multi-million pound roof.
Federer was also keen to test conditions under the new translucent 1000-tonne concertina structure but had to make do with playing in glorious sunshine during his 6-3 6-2 6-7 6-1 third round victory over Germany's Philipp Kohlschreiber.
Despite dropping his first set at this year's tournament, the signs looked ominous for anyone harbouring hopes of preventing the five-times former champion from reaching his seventh successive final in south-west London.
French Open runner-up Robin Soderling, who continued his seamless transition to grass with a 7-6 6-4 6-4 win over Spaniard Nicolas Almagro, will be up next for the Swiss.
Serena Williams also came prepared for a wet day as she walked out on Court Two wearing her customised white raincoat.
However, the American did not need it as she stormed into the fourth round with a 6-3 6-4 win over Italy's Roberta Vinci.
With Williams dashing past her first three opponents, Daniela Hantuchova could be in for a couple of sleepless nights.
The slender Slovakian earned a date with the second seed thanks to a 6-4 6-3 win over Japan's Ai Sugiyama.
Ankle Sprain
Fourth seed Elena Dementieva, a semi-finalist last year, blew away fellow Russian Regina Kulikova 6-1 6-2.
But their compatriot, seventh seed Vera Zvonareva, handed Frenchwoman Virginie Razzano a walkover after failing to recover from an ankle sprain.
While fans on the outside courts were delighted the heavy thunder showers forecast did not materialise during the first few hours on Friday, Centre Court occupants were hoping the unpredictable British weather was true to form.
"Usually when I buy my ticket through the ballot, I'm always praying that the weather doesn't spoil my day because I come down from Nottingham," Chloe Marshall told Reuters.
"This time, I really want to see rain today as then I can tell everyone for the rest of my life I was one of the first to see the roof in action."
To catch a glimpse of wet weather she would have had to come into the grounds on Thursday when officials closed the roof overnight to protect the grass from rain.
Another tennis fan, Joshoda Batra, was also hoping to earn bragging rights by seeing the roof closed.
"We got dressed thinking it might rain today and it would be great to be the first to see the roof," added Batra as she folded away a newspaper announcing the death of singer Michael Jackson on its front page.
Like the rest of the world, Wimbledon was rocked by the unexpected death of Jackson at the age of 50 on Thursday.
"The things that he did was beyond iconic. Words can't express my shock and horror ... it's just terrible, terrible, terrible thing," said Williams.
Men's sixth seed Andy Roddick added on his Twitter page: "Oh my lord ... Michael Jackson died... RIP sad and surreal. Regardless of what you think of him he was completely revolutionary and will be missed."
