The ground was described as good to soft on Monday after 15 millimetres of rain on Sunday and overnight.
Though dry weather is expected in the middle of the week, there is a good chance of rain on Friday which again will come to their rescue.
"The ground was called good to soft after 15 millimetres of rain in two spells of rain on Sunday afternoon and into the morning," said Andrew Cooper, director of racing and clerk of the course. "It's been a muggy day (on Monday), with no more measurable rain.
"I don't think we're expecting any further appreciable rainfall until Friday, when there is some rain coming in from the west, breaking the weather down after a dry middle part of the week, but that's a long way off.
"We were getting quite anxious to see some rain. We had dried out quite appreciably. Before that rain on Sunday afternoon, we certainly would have said good to firm, with firm in places.
"We had left the course alone with the threat of thunderstorms at some point during Sunday. We were grateful to see the rain and are shaping up to some really nice ground by the end of the week.
"It may get a little warmer towards the end of the week, but we're only talking up to about 24C maximum, nothing too drastic, but it will dry and it will settle. Monday is way off from Friday, and even further from Saturday at this time of the year.
"In this job, if you have a two-day meeting you sometimes say a prayer for three millimetres of rain overnight between the two days. It makes this job so much better.
"We were pleased to see the rain. We did need it, and it's took us from pretty quick to slower than good."
There will be a record prize fund of £1,625,000 up for grabs in the premier Classic, after the prize money was boosted by two supplementary entries, Dante winner Permian and Khalidi, at the five-day confirmation stage.
"With two supplementary entries, at a rounded up £1,625,000 this year's Investec Derby will be the richest race ever run in this country," said Cooper. "This year the advertised value has been put up to £1.5million. Last year it was £1.325m.
"In broad terms, the pot gets added by about £62,000 per supplementary entry and the remaining £23,000 goes towards the owners' entry contribution to the race.
"We've added £1,100 to round it up to £1,625,000."
Cooper was delighted at the number of horses left in the big race: "It's a very open race and it's hard to be too confident.
"I thought we'd probably be at about 17 or 18 runners at this stage. There's 20 in, so all are guaranteed to run. It's a fascinating race and it looks like we're going to get a big, competitive field.
"The race takes on different guises in different years. Sometimes you'll get a hot favourite against 10 or 11 others. This is one of those ones where a lot of connections are clearly thinking of giving it a go."
