Tectonics is more a tool to help you map and can inspire thoughts of volcano and earthquake prone areas, as well as where island chains and mountains logically belong. Currents are far more important to climate.

Tectonics can also assist in creating desert-like areas despite rainfall, due to simply having infertile ground. Australia, as I recall, in parts has more than adequate rainfall to not be desert (and I think it heading more and more north toward the equator where it will get more rain due to the ITCZ) but remains barren rock. Why? It sits in the middle of a plate and therefore has had no real volcanic activity for an extremely long time, and volcanism is a major player in fertility.

I always recommend the ITCZ map, not for every month! But to just take a look at the extreme north and south meanderings and how those play across the continents. For instance, one belt of mountains on my map, we figure that now and again the ITCZ will travel north above them and provide massive rainfall, but most seasons it would hang to the south of the mountains, leaving it very arid most years and with a short rainy season others. This gives the region good character.

Ever decide the direction the world spins?