What “Wet Bulb” Temperature Actually Means
The term wet bulb temperature describes the lowest temperature the air can reach when water evaporates. It combines two factors: heat and humidity.
When humidity is high, sweat cannot evaporate efficiently from the human body. This prevents natural cooling and makes hot weather far more dangerous than dry heat.
Meteorologists measure wet bulb temperature using a thermometer wrapped in a wet cloth while air passes over it. The reading shows how effectively evaporation can cool the air.
Why Wet Bulb Temperature Is Dangerous for Humans
Human bodies cool themselves mainly through sweating. When sweat evaporates, it removes heat from the skin.
But when humidity rises, evaporation slows down. The body starts to trap heat instead of releasing it.
Scientific studies show that once the wet bulb temperature reaches about 35°C, the human body can no longer cool itself effectively. Even healthy people resting in shade can face life-threatening conditions within a few hours.
Key risks include
- Heat exhaustion
• Heat stroke
• Organ failure
• Severe dehydration
Wet Bulb Conditions in the Middle East and North Africa
The Middle East and North Africa (MENA) region is one of the world’s most vulnerable areas for dangerous wet bulb temperatures.
Coastal cities near warm seas experience the highest risk because heat combines with intense humidity.
Examples include
- Gulf coastal cities where summer temperatures often exceed 45°C
• Red Sea regions where humidity regularly surpasses 60–70%
• North African coastal zones during marine heatwaves
During extreme summer events, some Gulf locations have recorded wet bulb temperatures near 31–33°C, approaching dangerous human survival limits.
Why Coastal Areas Feel Hotter Than Desert Regions
Dry desert areas can record extremely high air temperatures, but they often have low humidity.
This means sweat can evaporate quickly, allowing the body to cool more efficiently.
However, humid coastal cities experience a different type of heat stress because
- Moist air traps body heat
• Sweat evaporates slowly
• Night temperatures stay high
This is why a 38°C humid day near the coast can feel more exhausting than a 44°C dry desert afternoon.
Climate Change and the Rising Wet Bulb Risk
Climate scientists warn that wet bulb temperature events are increasing as global temperatures rise.
Warmer oceans increase humidity levels in nearby coastal regions. At the same time, stronger heatwaves push air temperatures higher.
In parts of the Gulf, climate projections suggest that dangerous wet bulb thresholds could become more frequent by the end of the century.
This makes heatwave preparedness increasingly important across MENA cities.
Warning Signs of Dangerous Heat Stress
During extreme humid heat, the body may begin to struggle within minutes.
Common warning signs include
- Heavy sweating followed by dry skin
• Dizziness or confusion
• Rapid heartbeat
• Nausea or fainting
Immediate cooling and hydration are critical once these symptoms appear.
Safety Tip During Humid Heatwaves
During humid heatwaves, always pay attention to both temperature and humidity, not just the temperature forecast.
Limit outdoor activity during peak afternoon heat, drink water frequently, and seek shaded or air-conditioned spaces whenever possible.
