Too hot

Hi,
I'm due to go on holiday soon and the weather forcast has stated that it's going to be 34 degrees (C) all week. My friends are planning on doing a lot of walking and i've previously had problems with the heat before. When I get too hot I often faint (this has happened five times on holiday before). Is 34 degrees going to be too hot for me to walk? How much water do you think ill need to drink to avoid this?
Sorry if none of you are doctors - i'm just worried!
Thank you!

Just keep hydrated, have a water bottle at all times and drink constantly in sips rather than drinking a whole bottle and then not for another couple hours. 34 degrees isn't really that hot either, the humidity does play a factor as well. Try not to worry about it.

I went to Madrid recently and it was 35c most days. It was absolutely unbearable. We tried to do walking but we had to keep stopping to go inside for a drink and stuff. If you faint it's probably not a good idea to walk around a lot. Make sure you drink a lot of water - like a LOT. A good few litres a day and make sure you find out if the tap water is ok to drink and if it isn't, stock up on bottled. You don't want to be getting diarrhoea because it'll make you even more dehydrated. You could take an umbrella to keep some of the sun off you and try to avoid doing lots of walking during the middle of the day (12-3) which is usually the hottest!