Not sure how bad your weather is there, but Im assuming its not as wet as it is in Canada.
If your cabinet is only getting occasional wetting from blowing rains, than any wood will be fine if you apply a good coat of paint or oil based stain. I have a plywood covered garden shed I painted with barn red stain about 10 years ago, and the cheap builders grade 1/4" ply is still holding up great. Added some 1x2 pine strips and it looks like board and batten. 1/10th the cost...
If you want a wood look, as opposed to the stainless and granite, (which would be my preference here in Ontario) try and find a cedar or redwood type of wood, or possibly even a redwood veneer plywood may be available to you. Use an outdoor rated glue to glue them together with treated screws, or leave them butted up together for that pic nick table look.
Most woods will go grey once weathered, and most woods that are allowed to dry after getting wet will last for years or decades without treatment, so long as they are able to dry after each wetting.