How does the surface area and climate affect the rate of weathering?

The rate if weathering in a rock is determined by surface area, temperature, moisture and chemical composition. Surface area effects the rate because weathering occurs on the surface of the rock; therefore a whole rock will weather slower than that same rock in fragments. Temperature and moisture (climate) effect the rate, because weathering is both chemical reactions (hydrolysis, etc) involving water, who's speed is controlled by how warm the system is, and by physical weathering, often involving water (freeze-that etc). The chemical composition is in reference to how stable the rock is in s given environment, and is indicated by Bowman's Reaction Series.