ISOHYETAL
Important rainy seasons in the State are during south-west monsoon
(June-September) and north-east monsoon (October-December). About 60% of the
annual rainfall is received during south-west monsoon and 20% during northeast
monsoon. The average annual rainfall in the State is 2615 mm. The annual
rainfall in the lowland ranges from 900 mm in the south to 3500 mm in the
north. In the midland. annual rainfall ranges from 1400 mm in the south to 4000
mm in the north. In the highland. the annual rainfall varies from 2500 mm in
the south to about 5000 mm in the north. The morphology of the ghats is
attributed to be one of the major factors deciding the rainfall pattern.
Percentage variations from normal for monsoon rains are depicted below:
PERCENTAGE VARIATION FROM
(SOURCE: M.S. RAJAGOPALAN, K.T.JOSEPH:
METEOROLOGICAL CENTRE,