That is why they invented siesta time.

well during the summer people stay up longer at night than on school dayz so once they sleep they got 2 make up the hour s they stay up n the days are so long n boring that u get sleep out of boredom

yes because at night they can't sleep very well since it's already hot even at night

we need atleast 8 hours of sleep every night to be well rested and get enough energy. but this thing varies from person to person. you should be dozing off in a meeting for an instance if you didn't get enough sleep. If you had a good sleep, then you shouldn't feel drowsy during the day. another thing would be, people who take heavy lunch may tend to doze off - I don't exactly know how this phenomenon occurs but one thing for sure, it's happening to me. In my work, when we're having a meeting or seminar (which incidentally happening during noon time), I always fell sleepy. It's seems like the speaker is throwing a hypnotic tone towards me and makes me flaking out all the time. :)