• Cropping system can be planned by understanding the rainfall pattern.
• Rainfall analysis helps in taking decisions on time of sowing, scheduling of irrigation, time of harvesting etc.,
• Rain analysis is necessary for designing farm ponds, tanks of irrigation projects.
• Amount, distribution and intensity of rainfall are the important aspects of rainfall that have considerable influence on crop production.

Click the Respective Zone for Annual Rainfall

S.No.	Name of the Zone	Districts	Annual Rainfall (mm)
I	North Eastern Zone	Kancheepuram, Vellore, Villupuram, Cuddalore, Thiruvallur, Tiruvannamalai	1105
II	North western Zone	Salem, Dharmapuri Namakkal	875
III	Western zone	Erode, Coimbtore, Karur (Part), Namakkal (Part), Dindigul (Part), Theni (Part)	715
IV	Cauvery Delta Zone	Thanjavur, Nagapattinam, Thiruvarur, Thiruchirappalli, Perambalur, Pudukottai (Part), Cuddalore (Part)	985
V	Southern Zone	Madurai, Sivaganga, Ramanathapuram, Virudhunagar, Thootukudi, Tirunelveli	857
VI	High Rainfall Zone	Kanyakumari	1420
VII	Hilly Zone	Nilgiris (dindiugul part kodaikanal)	2124

SEASON	NORMAL IN (mm)
South West Monsoon	314.6
North East Monsoon	459.2
Winter	37.5
Summer	128.4
Annual (January-December)	939.7