Rain is liquid precipitation in the form of water drops. Drops with a diameter of less than half a millimetre are known as drizzle. Convective rain is referred to as showers. Showers generally last for less than one hour. Rainfall intensity can be 'light', 'moderate', or 'heavy'.
Heavy rain falls at a rate greater than four millimetres per hour.
Whilst the wettest day in Bristol saw just over 43 millimetres, The most rain ever recorded in the UK in one day was 279.4 millimetres at Martinstown in Dorset on 18th July 1955. This hardly compares with the world record of 1825 millimetres which fell in 24 hours at Foc-Foc, Reunion in the Indian Ocean. The wettest place in the world is reckoned to be Mawsynram in the state of Meghalaya, India. Here the average annual rainfall is 12000 millimetres. If you do not like the wet stuff, head for Africa in the Atacama Desert of Chile.