Hot weather
Hot weather is a joy for many travellers, but "too much of a good thing" can be annoying and even dangerous. This article covers ways of coping with the annoyances and avoiding the dangers.
Hot weather, is not just about temperature, as humidity also greatly influences the effects. The traveller's tolerance also comes into it; someone who is used to local weather may cope far better than a person from a colder climate. Wind can also be a factor; a cooling breeze can be quite helpful but a hot wind or a dust storm can make things worse.
For regions with a persistent and prolonged hot, dry climate with minimal precipitation, (also known as desert regions) a separate article exists at Arid region safety.
Even in a region not known for having a desert or (sub) tropical climate a summer "heatwave" can have an impact.
Understand
- See also: Astronomy
| mild | warm | hot | swelter | cooked | ||||||
| °C | 13 | 15 | 18 | 21 | 24 | 26 | 30 | 32 | 35 | 38 |
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| °F | 55 | 60 | 65 | 70 | 75 | 80 | 85 | 90 | 95 | 100 |
The Earth's axis is tilted by 23 degrees in relation to the ecliptic (the plane of its orbit around the Sun) and this causes the seasons. When your part of Earth is tilted toward the Sun, you get summer; when it is tilted away, winter. For any latitude, the angle between vertical and the noon sun ranges from latitude-23 at the summer solstice to latitude+23 at the winter solstice, and is exactly the latitude on the equinoxes. In the tropics — within 23 degrees of the equator — that range includes 0° so at times the Sun is directly overhead.
In general, the closer a place is to the equator the hotter it will be and the less variation there will be over the year. For example, Singapore is only one degree off the equator so the angle there ranges from 22° one way to 24° the other and the climate is uniformly hot all year; the record high and low temperatures are 36°C (96.8°F) and 19.4°C (68.9°F). Near the Equator you don't get the extreme heat (e.g. +50°C or +120°F) that you may encounter in desert environments such as Sahara, the southwestern U.S. or central Australia, but the humidity can make the relatively lower temperatures quite unbearable.
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In Edmonton at 53°N, the sun is 76° from vertical at noon in mid-winter, so winters are quite severe but in mid-summer it is only 30° off vertical so summers can be quite hot. In Northern and Central Asia, the world's most continental climates, the difference between winter and summer extremes can be almost 100 °C (212 °F).
Other factors also come into play. Large bodies of water tend to moderate the temperature of nearby places while high altitude makes a place colder, even in the tropics. Note, however, that these do not reduce the strength of the sun which may be hazardous even when the air is relatively cool. In fact, altitude increases the solar risks since there is less atmosphere above to protect you.
There are regions which are described as "Tropical", "Sub-Tropical" and "Mediterranean" in climate terms, which should be taken as a possible indicator of generally "hot" summers.
Clothing
- See also: Sunburn and sun protection
Choosing the right clothing can help a lot. Points worth considering include:
- "When in Rome, do as the Romans do."
- Light colours absorb much less sun than dark ones, so they are usually cooler.
- Loose clothing allows air to circulate much better than tight clothing. This both cools directly and helps perspiration evaporate faster for additional cooling. It may also keep biting insects away from your skin.
- A large hat protects your head. This can be important for anyone, but especially for balding men. A wide-brim is also recommended to reduce glare, but avoid cheap plastic 'sun visors' which have little value.
- A parasol reduces exposure to the sun. In many tropical climates, an umbrella is needed for rain and showers as well.
- You may need multiple layers of clothing, for example a jacket to put on in the cooler evenings.
Of course it is wise not to violate local taboos; for example a woman should not wear shorts or a miniskirt in some places, no matter how hot it gets. Also, clothes that make you stand out as a tourist may make you a target for scams, pickpockets and in some places even muggers. See the linked articles and the "respect" sections of country, region and city articles for details.
Heat waves
Heat waves are abnormally (and sometimes unexpectedly) high temperatures, that can range from a few days to an extended period in some instances, They along with high heat that is persistent in a location, can cause discomfort and health risk, even to those that are seemingly prepared.
Though a general definition of a heat wave is when temperatures at around 27°C (80°F) or above are occurring, its effect can be dramatically different depending on humidity, which affects the temperature that one feels on one's skin. A person experiencing a dry heat wave may begin to feel discomfort when it is 32°C (90°F), but the same temperature and 75% humidity would feel like 43°C (109°F)!
Also, what is a heat wave and what isn't a heat wave largely depends on where you are. What would be extreme heat during summer in the United Kingdom would be the usual high temperature in many parts of Northern Africa.
Coping with the heat
- Avoid strenuous activities outside, especially during the afternoon when the temperature is the hottest. In some regions it's not considered abnormal to take a break in the early afternoon, resuming any activity later when things are cooler.
- Drink lots of fluid as that will cool you down while at the same time replacing the fluids in your body exerted by the heat.
- It is a good idea to move, or try to stay indoors where shade and cooling systems are usually found, or go to a park and sit under a tree to avoid the sun.
- Prolonged exposure to heat can lead to Heat exhaustion. Children and elderly people are especially prone to heat related illness, from cramps to heatstroke. You should at regular intervals check how they feel, and go for emergency treatment as soon as the symptoms show up. You should also not necessarily leave them unattended in an overly hot location, such as a parked car or unshaded queue line.
- Do not leave pets in your car, as the inside car temperature can rise quicker than the outside, and can soon become both dangerous and intolerable.
- The UK NHS has some advice on how to cope with hot weather.
Medical issues
Heatstroke and heat exhaustion are life-threatening conditions which occur when the body can no longer control its temperature; body temperature rises and the victim becomes extremely ill.
High ambient temperature is a major factor in this, of course. Humidity is also very important; when the humidity is high, water evaporates more slowly and the body's normal method of cooling itself by sweating is much less effective. Any physical exertion adds to the problem. Dehydration can contribute to the problem by making you sweat less; you should always drink lots of water when it is hot. You should also take care of the minerals: you get some by ordinary food, but sport drinks or similar can be useful.
Heat exhaustion
Heat exhaustion is the less serious of the two conditions but should still be taken seriously. If not treated quickly it can develop into a life-threatening condition. Symptoms include:
- Tiredness and weakness
- Feeling faint or dizzy
- A decrease in blood pressure
- Headache
- Muscle cramps
- Feeling sick
- Heavy sweating
- Heavy thirst
- A fast pulse
- Urinating less often and having dark urine
If the affected person receives effective treatment they should recover within 30 minutes or so. Make sure someone stays with the patient until they have recovered. Treatment of the patient involves:
- Getting the person to lie down and rest in a cool place out of the sun
- Removing unnecessary clothing to allow the skin to breathe and perspire
- Cooling their skin with water (never use ice - a wet sponge or flannel will do)
- Fanning them
- Getting them to drink fluids (ideally this should be water, fruit juice, a sports drink or a rehydration solution)
Heatstroke
Heatstroke is very serious and should be treated as a medical emergency. If not treated it can cause organ failure and eventual death. Symptoms are as above for heat exhaustion but may also include:
- Unconsciousness
- Vomiting
- Confusion
- Seizures
- Disorientation
- High body temperature
- Dry and red skin
- Hyperventilating (rapid and shallow breathing)
Seek emergency medical treatment immediately. While waiting for help get the person into a cool area out of the sun. Cool their body with cool (not ice cold, but if ice is all you have then make sure it doesn't make direct contact with the patient's skin) water and fan them. Do not force an unconscious person to drink anything.
Heat shimmer and mirages
In certain areas, including expanses of sand or surfaced roads, mirages can easily form under the hot conditions. These are a form of heat haze or shimmer, that can give a distant object the appearance of being viewed on a water like surface. The object often looks expanded vertically, so that e.g. a low hill can look like a tower or town. A mirage can also make it appear you are seeing a distant lake or shore, when no such body of water exists.
These are an optical illusion; there is no water, the apparent reflection is just light bending as it passes between layers of hot air and layers of marginally cooler air (which differ in density). Do not be fooled!
Wildfires
In areas where there's been prolonged heat and an associated drought, the risk of wildfires is higher. Along with that problem, you will need to remember that wildfires themselves cause temperatures to rise in nearby communities.
When the heat breaks
When the heat breaks in humid climates there is a risk of thunderstorms, hail and flash floods. The dangers of these are covered in their respective articles; hail is covered in the thunderstorms article.