Conditions on the Grand National course improved after a dry day on Monday though the weather for the three-day meeting itself is unsettled.
The going for the Aintree showpiece was described as good to soft, soft in places. It was previously soft, good to soft in places.
"We had seven millimetres of rain overnight but it has been a nice drying day and I have changed the going on the Grand National course," said clerk of the course Andrew Tulloch.
"It remains good to soft on the Mildmay course and good to soft, soft in places in the home straight on the hurdle course.
"We should have another dry day on Tuesday, but there is rain forecast on Wednesday, while the weather is likely to be unsettled during the three days of the meeting.
"Temperatures will be around 11C to 12C. The courses are in good nick and we will be racing on the outer configurations on on Thursday, so as to have fresh ground for later in the week."