Hypothermia occurs when body core temperature drops below 35°C (normal is 37°C). Mild hypothermia (35-32°C) causes shivering and confusion. Moderate (32-28°C) causes slurred speech, loss of coordination, and drowsiness. Severe (below 28°C) can cause unconsciousness and death. In the UK mountains, hypothermia kills several people every year.

What conditions cause hypothermia?

The combination of cold, wet, and wind is most dangerous. You do not need sub-zero temperatures — most UK hypothermia cases occur between 0-10°C in wet, windy conditions. Getting wet dramatically increases heat loss (water conducts heat 25x faster than air). Exhaustion and inadequate clothing are major contributing factors.

What are the signs of hypothermia?

Early signs: persistent shivering, cold pale skin, tiredness, confusion, fumbling hands. Moderate signs: intense shivering then shivering stops, slurred speech, irrational behaviour, stumbling. Severe signs: shivering stops, barely conscious, very slow pulse, dilated pupils. If shivering stops without rewarming, this is an emergency.

How do I treat hypothermia in the field?

Stop. Shelter from wind and rain (group shelter or tent). Insulate from the ground. Remove wet clothing and replace with dry layers. Give warm sweet drinks if conscious. Share body heat. Do NOT rub limbs or give alcohol. For severe hypothermia, call 999/Mountain Rescue — handle the person very gently as rough handling can cause cardiac arrest.

CampCalcs

Hypothermia Risk Calculator

Assess hypothermia risk based on temperature, wind, wetness and exposure time.

Air Temperature

Temperature for this process

Wind Speed

Speed or velocity

Wetness

Enter the wetness

Clothing

Enter the clothing

Activity

Enter the activity

Exposure Duration

Duration of the process

How We Calculate This

Risk Score (0-100)

Combines: wind chill temperature (0-40), wetness (0-40), clothing adequacy (0-35), activity level (-10 to +20), and exposure duration (0-15).

Key Principle

Cold + Wet + Wind = Danger. Wetness is the single biggest risk amplifier. Stay dry above all else.

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates. Always verify conditions and use proper safety equipment outdoors.