Even if it's cloudy, protect yourself from harmful UV rays by using a suncream with a high protection factor. Reapply it every couple of hours and don't forget to protect your ears, lips, hair parting and the tip of your nose with sunblock.

Stay in the shade between 11am and 3pm when the rays are at their most damaging.

Sunburn leads to premature ageing and an increased risk of skin cancer. To avoid it, make sure you:

Wear a wide-brimmed hat and loose clothing
Choose sunglasses with UV filters to protect your eyes
Protect children and babies from direct sunlight - apply a suncream with SPF25 or higher, and make sure they wear hats and long sleeves Keep babies under 12 months out of the sun

Overheating can cause sunstroke or heatstroke. To avoid its effects:

Avoid strenuous activity during the hottest part of the day Drink plenty of non-alcoholic liquids to balance the loss of body fluid through perspiration

This irritable red rash is caused by increased sweating and excessive heat.

It can be controlled by taking tepid showers and dabbing the affected areas with calamine lotion. Wear loose-fitting clothing to help reduce irritation.

Once your body has acclimatised to the heat, the rash should settle down.

The sun's rays can be just as dangerous when they bounce off snow and ice. Always use a suncream of SPF15 or above and wear sunglasses or goggles, even in cloudy weather.

At high-altitude resorts, you'll probably notice the effects of thinner air - you may feel very tired, very quickly. To help lessen the effects, start your pre-ski fitness regime at least six weeks before you go on holiday. Start on the lower slopes and work your way up to higher altitudes.

Acute mountain sickness (AMS) causes dizziness, nausea, raging headaches and radical changes in personality and behaviour. It's a life-threatening condition. If symptoms arise in any of your group, alert the ski patrol or mountain medical corps, and descend the mountain immediately.

Hypothermia is a potentially fatal condition that occurs when your body temperature falls beneath 35°C (95°F).

The main causes are cold weather and exposure to wind. It's prevented by wearing appropriate clothes, with sufficient insulation and wind- and waterproof outer layers. A hat is also important.

The main symptom is feeling cold. However, often the sufferer won't complain about this. Changes in behaviour soon follow, including irritability and aggression. As the condition progresses, the person becomes confused and drowsy. It's essential to be aware of these signs, particularly when touring or skiing off-piste.

Frostbite occurs when the extremities (fingers, cheeks, ears, nose and toes) get so cold their temperature drops below freezing. If noticed quickly, it's fully reversible. If not, it can result in loss of tissue.

Symptoms include an uncomfortable coldness that becomes painful, then numb.

If you suspect someone in your group has hypothermia or frostbite, stop immediately. Make sure they're wrapped up warm, in a safe place. If you can't find shelter, huddling together should warm them up but this will take time. Continuing to ski, drinking alcohol or smoking cigarettes will do nothing to help the victim and may make things worse.

If frostbite or hypothermia is advanced, alert first aiders on the slopes. The local hospital is the best place for emergency medical treatment - it's better to be safe than sorry.