After a weather-hit opening day on Sunday, when only 10 matches were completed, 66 singles matches were scheduled for Monday with reigning men's champion Stan Wawrinka first up on Philippe Chatrier Court against Czech Lukas Rosol.
Weather forecasts predicted the heavy rain would subside in the afternoon to leave sunshine and showers.
The rest of the week look more settled, according to forecasts, although showers and thunderstorms are likely in the French capital at the weekend.
