Hamilton's eight-race fixture on Friday evening has been cancelled due to a waterlogged track.
An inspection was called on Thursday afternoon to determine whether the meeting could go ahead after a number of false patches of ground were found inside the final two furlongs, but these had not sufficiently dried out in time and the fixture was called off.
Clerk of the course Harriet Graham said on Thursday: "We've tried as hard as we can to get the meeting on but these false patches on the course are unlikely to dry out in time. It is warm and dry today but also quite cloudy and the grass is still wet, so we haven't even started drying.
"It's a tough decision but probably the right one, rather than getting everybody here and still having to call the meeting off tomorrow. If we hadn't been trying hard to get this on we could have called it a bit earlier, but that's the way it is."
Hamilton has been hit by torrential downpours over the past two days, with Graham reporting 54mm of rain in that period, which led to the false patches emerging. There are also showers forecast for Friday evening.
Persistent rain forced Ayr to abandon its meeting on Wednesday with five races to go after jockeys flagged up areas of false ground.
Hamilton's next fixture is scheduled to take place on Thursday, August 13.