The weather in Samui in March is fantastic, if a little hot. The average air temperature is a scorching 29°C/83°F, with the average humidity of 63% to 91% rising as the month goes on and only gentle breezes from the southeast to cool you. The sea temperatures are also quite warm at 27°C/81°F, while the pancake-flat surface conditions and excellent underwater visibility make this the start of the peak diving and snorkelling season, with the chances of seeing whale sharks being relatively high. The chances of rainfall, in contrast, are quite low, with an average of just 30mm of rain expected over just four days of the month, usually around dusk or at night, which can make for really striking sunsets.