Police and other agencies are looking at opening a third car park site. They are monitoring wind speeds at the site. Chief inspector Nick Heelan said there are very strong winds at the festival.
He said structures there are licensed for a maximum wind speed to ensure public safety and this will be regularly reviewed.
Chief inspector Nick Heelan from Hampshire police says roads around the campsite are now all clear.
His message to people en route to the festival is leave cars at home and come by foot if they can.
Robin Hill country park is now open for extra cars which has a hard surface for parking. There is a special bus service operating from this site now.
Sally Fairman, 37, from Chessington, Surrey: "We usually come from Southampton, but we took the hovercraft from Portsmouth this time. There was one bus every two hours.
"It's all a bit strange. We've lost the gazebo, but the tent's still standing and we're looking forward to some music now."
Georgia Jones, 23, from Cornwall, said: "It was a nightmare. We got the ferry alright, but the bus took two hours and it was open top! We got pretty wet and the bus couldn't even get to the site so we had to get off and walk for miles.
"Putting up the tent was difficult, but people were helping us. It's friendly and nice here, no one seems to have been put off by mud. Our tent is still in one piece, but some have blown away. There's not one bit of grass just mud."
Isle of Wight Council urged people coming to the island to try to make their own parking arrangements due to the waterlogged car park. Stuart Love, director of economy and environment for the council, encouraged people to come on ferries as foot passengers.
He said the council is busy finding extra car parking sites which can be opened today to alleviate the jams. Organisers are negotiating with private landowners.
It's not good news for anyone at the festival - the weather does not look to be improving anytime soon:
Festival goer Max Ritchie, 16, from Gillingham, in Dorset, said: "It's pretty awful in here to be honest - mud everywhere. We came over on a friend's boat. We had to walk for miles and it's not very nice. Camping last night was an experience, but there was a really good atmosphere."
Organisers of the Isle of Wight Festival said refunds will be discussed after the weekend.
A spokeswoman for Wightlink, which operates ferries from Portsmouth and Lymington to the island, said services had resumed as normal this morning. She said: ''Our ferries are currently running to schedule and on time.''
Members of Vectis 4x4 Response, a voluntary group which helps in emergencies, helped tow 358 vehicles to the car park last night. John Marr, of Vectis 4x4, said: ''We had eight vehicles on site. Even with a police escort to get us in, it took us an hour to get there. ''We moved 358 vehicles that were stuck in the mud. There is only one way into the car park and the conditions were the cause of all the hold-ups. We aren't to blame, but we did our best.''
A statement by Hampshire Police placed on Twitter said: ''More car parks are open around the Seaclose Park site but IW Festival goers and residents are advised to still expect significant delays today.
''The festival's emergency liaison team is working closely together to explore other options to reduce traffic queues and minimise disruption as soon as possible.
''These options include opening other car parks across the island.
''Our priority is to clear existing traffic on the island and provide more welfare and refreshments to motorists in queues.
''Some motorists remain parked at Newport Football Club.''
The organisers of the Isle of Wight Festival are recommending people still on the mainland do not travel by car. Festival goers are being encouraged to travel to the island on the foot passenger ferry services instead.
The traffic between the festival site and Cowes has now eased. The Echo's Shelly Fountain reports you can now drive from the town to the site in just 10 minutes.
It is not yet clear about the traffic conditions from other ferry terminals, such as Ryde.
YouTube user SB Clarke has uploaded this clip of the traffic on the island.
Entertainments editor, Lorelei Reddin, says entrepreneurs are earning cash from using their boats to ferry people directly to the Isle of Wight festival sites.
As well as the usual water taxis, anything that floats is being used to avoid traffic gridlock and access the festival from the Medina River side.
Daily Echo reporter Bethan Phillips was among the revellers trapped in the traffic mayhem.
She caught a bus from Ryde just after 6pm but after an hour in a queue she resorted to walking the five miles to the campsite.
She said: “As soon as we got to Ryde the traffic was at a standstill and it was complete gridlock. We carried all our bags for five miles in the torrential rain and got absolutely soaked because nothing was moving at all. Some people said they had been in their cars for eight hours.
“When we got there nobody seemed to know which gate we were supposed to be going in. It was chaotic. The site is like a mud bath. There is no grass, just mud. It takes a lot to annoy festival-goers but this is something else.”
All cars entering the site are now being towed into the car park. Drivers are being asked to find out where the towline needs to be attached to their vehicle.
Aggregate is being brought onto the car park site to help shore up the ground to make it easier for cars to drive on.
A number of bus services on the island have been suspended, as they cannot make their way through the traffic, meaning workers and school children are having to walk to work and school.
Isle of Wight MP Andrew Turner has this morning criticised organisers over the gridlock on the island saying "90,000 is too many."
He said: "The weather has played a part – that is beyond the control of organisers. However the ground was already wet and recent rain has been forecast for some time; expected traffic can also be forecast with some accuracy. Despite all that it appears that inadequate contingency plans and preparations were in place."
The MP raised concerns that the traffic mayhem could be repeated as revellers leave the festival site. He added: “Most people are not killjoys – they expect some inconvenience over the Festival weekend – but there must be a limit. That limit has been reached. The permitted Festival size was increased to 90,000 this year – that is too many and not all the tickets have been sold; if they had been the problems would be even worse."
Many festival-goers last night resorted to sleeping in their cars after they were stuck in paralysed traffic for hours. Some say they have been in their cars for as many as 20 hours.