It's easy to look at a tyre tread pattern and determine fairly accurately how much grip you will have on a wet road.
The main reason for the grooves is wet weather, as well as better grip on loose surfaces and gravel roads.
The wider, straighter and more direct the grooves, the better. A tyre with a complicated tread pattern, might provide extra kilometres and less road noise, but it might not grip as well on a wet surface.
Avoid tyre flex by increasing tyre pressures above the comfort-biased level suggested by the manufacturers.
Firmer is safer in almost every respect, it will usually increase tyre life and improve fuel economy, so try 252 kPa (36psi) for normal use and 280kPa (40psi) for long trips.
Always keep in mind on a wet day that half-worn tyres have lost half of their drainage capability.