The diversity of the geographical features of the state has resulted in a corresponding diversity in climate. The High Ranges have a cool and bracing climate throughout the year, while the plains are hot and humid.
The average level of annual rainfall is quite high when compared to other Indian states, almost three times higher than in Karnataka while twice than in Tamilnadu. The state basically enjoys 4 types of climate such as Winter ,Summer ,South West Monsoon and North East Monsoon .
The winter season sets in during the month of December and continues till end of February. During this season comparatively there is less rainfall especially in the northern parts of the state.
Winter is followed by the summer season. Its tarts in February and continues till May. Temperature is very high during this period. Occasional showers with Lightning is a characteristic of this season. Kottayam receives the highest rainfall during this season.
South West Monsoon
The South West Monsoon begins either in the end of May or in the beginning of June and fades out by September. Moving towards north, this seems to gain intensity. During this period Peerumedu in Idukki and Vaithiri-Kuttiyadi range in Malabar receive the highest rainfall. The rainfall is comparatively low in the Lakshadweep islands. In the southern areas the monsoon is around 40-50% and in the northern areas it is around 80%.
North East Monsoon
The NorthEast Monsoon commences in October, dry weather setting in by the end of December. The Kanjirappalli-Peerumedu range and Kuttiyadi area experience the abundance of NorthEast Monsoon. The northern parts of the state account for a mere 10% of the annual rainfall.
The annual range of temperature is comparatively low in Kerala. The coastal areas record a maximum temperature of 320c and a minimum of 220c.The interiors record a maximum of 370c during summer. In the coastal area it is hot and humid during April-May while cool during December-January.