What is the beach temp variance from day to night? also, is the beach warmer when it rains?

my friends were having a big debate, so i need some answers so they can stop arguing.. one says the temp of a beach doesnt change, on cold days or at night the beach feels warmer because your body temp is cooler, and visa versa, the other is saying that for some reason unknown to her, the beach temp raises at night and when it rains.. please help!|||Apparently %26#039;the beach%26#039; only variates a few degrees throughout the whole year. Its the air temp which influences our option to swim or not.