Cripplegate Lane both ways from Millfield to Cedar Drive near Southwater is closed due to flooding.
Slow moving traffic has been seen on the A21 southbound by Baldslow.
Congestion has also been reported on Dittons Road in Eastbourne and by the roadworks in Polegate leading to the A27.
Delays are expected on the A27 heading towards Southerham Roundabout and on all roads leading to the roadworks at Earwig corner.
Traffic has also been seen both ways on the Chichester Bypass between Fishbourne and Portfield Roundabout.
Delays are expected to be caused by heavy rain from Hailsham up towards Heathfield.