What is the best way to stay cool during the summer heat?

If one has an air-conditioner, that would be a good way to keep the room, house, cool. I have seen some people who just have to be with a fan. One has to stay indoors, out of the heat waves, drink a lot of water. If I have the chance, I would take a swim in a cool swimming pool !

The best way to stay cool during the summer? You mean physically or mentally? If you mean the former, the best way I think is to stay at an air-conditioning room, which will make you almost forget how hot it is outside. If you mean the latter, I think the only way is not to consider those annoying things. If your brain could stop thinking for a while and have a short break, I'm quite sure that you may feel very comfortable in that period of time.

Avoid dark clothing, wear a hat and also stay hydrated. That should make things at least a little cooler.

I think it really depends on what resources you have available. There is a lot of times where its rather easy to stay cool if you just sit in a nice shaded region, whether indoors or outdoors, with a nice cool drink or perhaps some ice cream. You cannot really go wrong with some ice cream. Of course, if you have an air conditioner, there are few things that beat just staying outside from the heat in the air, until it all in fact blows over. At the very least during the hottest, most bitter parts of the day. In the days before air conditioning, I also found that a nice, ice cold bath felt rather liberating at ninety some degrees. Granted, that is really not something that is for everyone to say the very least. However, it is one way to cool us down. A cold bath or a cold shower or even just going outside with the hose or in the water sprinkler, that is really something that is cool. There are many ways to remain cool but keeping out of the heat when you can and not pushing yourself to the point of heat exhaustion is something that works wonders no matter how you slice it.

sunglasses will make us look cool during summer but i think that's not what you mean For me, i like to stay indoor and use air conditioning to stay cool in the summer.

Tank tops, shorts and a drink with a lot of ice!

Well, all of those are excellent, if you have them readily available. But when all is not readily available, staying hydrated will keep you cool and comfortable. Being hydrated is the most important during hot weathers. It will allow your body to readily replace liquid such as your sweat, which comes out of your body excessively during hot weathers. Usually I also try to wash my face during hot weathers, whenever possible. Sometimes I don't bother drying up the water, just enough so my face is left moist and allow the breeze to come by my face and cool the water even further. But overall, staying hydrated will keep you comfortable and functioning during hot weathers.

Staying in doors with your A.C. on.