Well, Greece is a warm country with its surplus of heat and sun, but nothing to really worry about if you are prepared and know a few tricks. We have a heat wave or two (some of the worst years might even score three) but they are limited to the bigger cities of the mainland and we manage through them like Northerners do with the cold and snow.
First thing you must have in mind is to take it easy. Heat alone can be exhausting especially if you come from a very different climate and didn’t have time to adapt, or a Greek friend to show you the ropes. So don’t plan a hectic schedule trying to see every last bit of, let’s say, Athens in just a couple of hours; especially on days when temperatures are expected to be in the 45°C (around 110°F) region.
You will do well to start your sightseeing tour as early in the morning as you can. Get info on visiting hours of the archeological sites you want to see and be there a good 15 minutes before the gates open. It will still be quite cool in the morning, and you won’t have to cope with the crowds that make heat even worse. This way, before the sun gets up and burning-hot, you will be ready to leave open sites and go indoors, to a museum, benefiting from the air-conditioning. Then have a break in an air-conditioned restaurant or a midday siesta rest back at your hotel, if it is near, for the 1pm to 5pm period – when the heat is peaking.
Ask for your guide to recommend the cooler spots on your route, like the Botanical Gardens in the center of Athens, or the city’s beach front called ‘the Athens Riviera’ to enjoy the cooling sea-breeze in a cafe. As in any city, some places are hotter than others. Do not overestimate your strength, especially if you are not familiar with heat-wave conditions. Don’t assume you will manage to walk a mile or two under the sun in midday carrying your luggage, or after an eight-hour flight. You will feel like an extra from ‘The Bridge on the River Kwai’, sooner than you think.
No matter what your fashion ideas or tropical-dressing stereotypes are, forget about them and dress for the heat – don’t get undressed because of it. Wear light, bright textiles during the day, covering as much of your body as you can. It may look cooler to roam around in minimal, tight cotton- tank-tops and shorts, but in reality this style has the exact opposite effect. Anything exposed to the sun will get initially sundried, letting vital body liquids to evaporate, making you rapidly feel tired because of dehydration and increased core temperature. The next step is getting sunburned and no, it is not the first step to a good tan: it is the beginning of pain. So, wear t-shirts or, even better, long-sleeved ones and loose trousers instead of shorts – as baggy as you can, so that the air can circulate freely. In case you are about to visit monasteries and churches, then this garb will also comply with the dress code enforced in places of worship. Avoid anything black or dark-colored during the day because you will get as hot as a solar water-heater. Save your darker clothes for after sundown when the brighter ones would invite mosquitos.
Get an isotonic drink instead of coffee if you thing you are about to start seeing camels anytime soon. Eat something light and slightly salty before you feel hungry. You can get cheap, delicious fruit in grocery stores anywhere in the cities. Coffee is dehydrating so get your doses early in the morning while it is still cool. A large, ice-cold beer – or a …fridge full of them – along with some “souvlakia”, might sound like the perfect booster, but don’t indulge in them before sundown. In fact avoid alcohol and heavy eating if you are planning to get back under the sun and the heat – it will be a punishing experience. This is one of the reasons why we Greeks eat late after sundown and kitchens stay open till very late... And remember that you can get street food and alcohol all night long.
Wear sunscreen, sunglasses and a hat as big as you can find. A light-colored baseball hat is the minimum. Some guys may laugh at your sombrero but they won’t be laughing in the evening when they get back to the hotel with a splitting headache and a sun burn on the back of their neck – with a silly white stripe from the camera’s leash across it. Avoid flip-flops, as you will eventually have to walk on slippery(!) pavement or rough terrain – you might end up with a sprained ankle, various cuts, or have one slip off your foot as you are about to step onto +70°C (+158°F) asphalt. Prefer sandals that tie up or summer sneakers.
Parasols are a good portable shade but not always practical – when in crowded or tight places – and you have to carry them around all the time. I would easily substitute one with an extra bottle of water. Water bottles are sold everywhere around the city but you might need to drink faster than you can get them – especially in archeological sites – to keep well-hydrated. Always remember to drink before you feel thirsty.
Almost all indoor spaces in Greece have air conditioning. The quick transition between environments of different temperature can prove punishing to the body. Stepping out from a shop or restaurant – where the ambient temperature is maintained at around 18°C (65°F) – your body is exposed to a sudden surge of more than 20°C (35°F). Predictably, this is a kind of shock that can threaten some of the more vulnerable people, like the very young or the elder. The opposite – entering an air-conditioned space from the street’s heat – might feel nice, but it is equally dangerous, as the bodily shock can – in extreme cases – even result in a stroke. The best advice is to anticipate sudden changes of temperature and plan ahead in order to give your body some time to adjust to the new environment.
To sum it up: Cover yourself, don’t run around in midday, drink a lot of water (no alcohol and fats before sundown) and take it easy.