Rain or showers occur now and then at most places. Occasional rain, or occasional showers, implies that precipitation occurs for less than half the time. Fog, Mist, Haze Are terms to describe reduction in visibility. Fog limits visibility to less than 1 kilometre, while in mist or haze you might be able to see as far as 10 kilometres. Less than 0.2mm in 10 minutes.
Puddles form slowly if at all.
0.2 to 1.0mm in 10 minutes. Puddles form rather rapidly, downpipes flow freely, some spray over hard surfaces. Greater than 1mm in 10 minutes. Rain falls in sheets, makes a roaring noise on roofs. For Snow or Drizzle Visibility greater than 1km.