Hi Toby
There’s no doubt that the winter fishing on the south and west coast can be spectacular – it is very weather dependant however. This doesn’t affect the temperature of the water but rather your ability to fish.
The South eastern and southern counties of Wexford, Waterford and into east and mid Cork have always tended to switch off around mid December through to April and even May. Whilst patchy fishing is only beginning now on this coastline and wont really pick up speed until possibly late June early May – some of the best fishing is priming on the south west coastline as we speak.
As a traveller to this country to catch bass, been here at the right location, tide and time is always a big challenge so my best advice to you is
South eastern, southern through to mid south western coasts are really at their best from June to October – there are of course some small exceptions to this and weather opportunities to be had from time to time
South western and up to mid west perform pretty much throughout the year once weather is on your side – there are again ‘local’ periods of phenomenal fishing which appear in the calendar – as a visitor to these areas early springtime like now and later through September, October, November and even into January and later are superb.