Basically as soon as the bass reappear on the south coast we start getting them on surface lures, and catch on them pretty much until the drop into deeper water at the end on the year. To be honest topwaters seem to be at their best during the period of the highest water temperatures, but never write off a surface lure in shallow water no matter what the time of year.
as soon as they turn up in late april or early may(depending on water temps) on the west side of the island , the locals are straight at them with surface lures,particularly chug bugs, fish upto 8.5lb were taken on them this spring......... best time is of day is from first hint of daylight in the morning until the sun comes up,or if its cloudy then you can continue longer, and then the last two hours of light and well into darkness .
I start using Surface Poppers in May on the coastline from Aberdaron to Barmouth but I do not use them in the Menai Straits until mid July as the Bass are pre occupied feeding on Crab and Sandeel until then it would be wiser to use diving lures of a Sandeel pattern but as already mentioned water temp plays a big part , I will start using Surface lures as soon as species like Sprat and Mackerel move into the Straits and with also juvenile Pollock which start moving onto the Kelp beds and ledges,which you can see on the surface at dawn and dusk and Bass love them.
I normally start with small surface poppers then use larger ones depending on which bait fish is around and will only use them if I am sure there is a lot of fish about or if I am searching a stretch of beach on foot to locate fish quickly,I will usually walk over a mile or more in search of Bass as I very rarely stay in one spot unless the fishing is very good,I will start 3 hrs before low and walk uptide along the beach as bass travel with the tide along my fishing marks on the Straits not against it as many locals think so.