First link gives you a forecast for the wind …….
Second link gives you an idea of the swell , webcam at Ashburton river mouth
Last link gives you the actual wind etc
And keep in mind , the wind can often be onshore at Birdlings ……yet 5-6kms down the spit at Baileys it can be blowing offshore ….
I hate to say it , but spring has got to be the worst time for fishing on the coast ..west coast I mean ….feb/march is the best over there … ya take ya chance I guess …
Purely from a conditions point of view of course