South west monsoon is the rainy season of the island of Sri Lanka which blows during the months between May and June. It is the monsoon which affects only south western quarter of country like Galle and Colombo. It is the best time to visit Sri Lanka with the possibility of enjoying the rains.
North east monsoon is experienced across the island Sri Lanka between October and November. This monsoon affects the whole country. It is the time when the country weather is completely unpredictable. This monsoon can be lighter, sporadic or can even be very strong. It is not the best season to visit Sri Lanka.