I think it probably is.Raspberries love moist conditions at their roots.
Water them well, very well, then invest for the future. Buy lots of mulched bark and spread it round the base of the plants. Do this to a depth of 5cm / 2 in. It will last three or four years before it needs a top up. It will totally eradicate the need for weeding and will keep those roots truly moist but not water-logged.