there some great clouds going by at the moment which reminded me that ages ago i said i was going to ask a geography teacher and a meteologist why it doesn't rain as much first thing in the morning (ie why i usuallly manage to avoid rain on the way to work).

the geography teacher didn't even believe my hypothesis. she lives in a rainy town in the west of town and hasn't done much teaching for a while as she's been making babies. so she's probably forgot.

but our friend the meteologist sent the following:

You are quite right that it is more likely to rain in the afternoon particularly in the summer with showery type rain. Showery type rain comes from convective clouds and for convection you need wamer surface so air near surface can warm up and go up (convect!) To warm surface need sun, longer sun been out warmer surface, more convection more likely to have rain. In some parts of the tropics you can set your watch by when the rain starts in the afternoon.

Non-showery type rain (due to "weather fronts") dont give a stuff about the time but thats the type which seems to rain all day (or more)

So now we know !