At the second rain disruption, champion Roger Federer had taken a 6-2, 6-3, 4-3 lead over Frenchman Sebastien Grosjean, while second seed Andy Roddick was leading Croatian Mario Ancic 6-4, 4-3.
Play in the men's semi-finals at Wimbledon was suspended at 1815 GMT on Friday, the second rain disruption of the day at the All England Club.
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Play resumed at just after 1700 GMT after a 4 1/2-hour interruption and champion Roger Federer had taken a 6-2, 6-3, 4-3 lead over Frenchman Sebastien Grosjean when the rain clouds appeared again.
Organisers had moved the second semi-final between Andy Roddick and Croatian Mario Ancic from centre to number one court and the American second seed was leading 6-4, 4-3.
Rain is also expected on Saturday when the women's final between Serena Williams and Maria Sharapova is scheduled to take centre stage.
After two days were lost to the weather in the first week, forcing organisers to schedule games on the middle Sunday, the first two days of the second week escaped the rain.
Despite rain on Wednesday and Thursday, the tournament was back on schedule to finish with the men's finals on Sunday before Friday's disruption.