Sorry, Timmer, but it's Wimbledon fortnight and Glastonbury festival: therefore it's bound to pee down with rain for days on end!
I took a gamble and booked a day out in Weymouth with my family last Saturday using this service - and I have to say, the weather played surprisingly fair for us. It was absolutely glorious! There were a few extra passengers heading for Glastonbury festival (which was by then already well under way) and a few locals making short journeys to go shopping or visit friends along the route, but although the train was still fairly packed on arrival at Weymouth I'd judge that at least 75% of those using it were trainspotters and enthusiasts rather than genuine daytrippers.