CLIMATE

Karaikal, situated on the east coast of India, near latitude 11° N in the deltaic region of the Cauvery, experiences tropical maritime type of climate with small daily range of temperature and moderate rainfall.

Karaikal has an annual average rainfall of about 126 cm, 68 percent of which occurs during October to December. The amount of rainfall during the south-west monsoon period is small, being less than 20 per cent of the annual. November is the rainiest month, accounting for about a third of the annual total.

In a year there are on an average about 55 rainy days, i.e. days with rainfall of 2.5 mm or more.

The level of temperatures in Karaikal is about the same as in Pondicherry. December and January are the coolest months with the maximum temperature at about 28° C and the minimum at about 23°C. However, minimum temperature as low as 16oC have been recorded.

The level of humidity and the pattern of cloudiness and surface winds are the same as in Pondicherry. Although slight variations in the month wise occurrence of depressions and storms are noticeable, thunder-storms generally occur during April to November, particularly in April, September and October.

Tidal Condition

Tides in these areas are semi diurnal with two highs and two lows during the day. The tide levels during spring and neap tides of Karaikal coast are given below:-
a) Highest High Water Spring (HHWS) - + 1.18m CD
b) Mean High Water Spring (MHWS) - + 0.65m CD
c)  Mean High Water Neap (MHWN) - + 0.47m CD
d) Mean Sea Level (MSL) - + 0.34m CD
e) Mean Low Water Neap (MLWN) - + 0.20m CD
f) Mean Low Water Spring (MLWS) - + 0.03m CD
g) Chart Datum (as defined in NHO Chart No. 357) - 0.00
h) The simulated storm surge along the Karaikal coast is 1.0m waves

Wave
Waves predominantly from NE, ENE and E during SW Monsoon and S, SSE, SE, SW and SSW during NE Monsoon approach the Port Site. From the monthly distribution of wave frequency, it is observed that four months of the year waves are from the NE Quadrant and the other eight months waves are from Southern Quadrant.

Currents

The Tidal current along the Karaikal coast is 0.5 knots or 0.25 m/s. The wind driven current due to the wind drift corresponding to a wind speed of 50 m/s during cyclonic conditions would be 1.5 m/s. In addition to the above two currents, piling up of water against the coast during the passage of cyclonic storm causes the sea surface to slope upwards towards the coast, which produces a slope current.