The perception of coldness is influenced by several factors, including ambient temperature, humidity, wind speed, and personal factors such as clothing and activity level. In certain conditions, 0-5°C can feel colder than temperatures as low as -15/-20°C due to the following reasons:
Wind Chill Effect: Wind speed significantly affects how cold we feel. Even at higher temperatures, if there is a strong wind, it can rapidly remove the thin layer of warm air around our bodies, leading to faster heat loss through convection. This can make 0-5°C with a strong wind feel colder than a lower temperature like -15/-20°C with calm or light winds.
Relative Humidity: Humidity is the amount of moisture present in the air. In colder temperatures, if the relative humidity is high, the moisture in the air can condense on our skin, making us feel damp and increasing the rate of heat transfer from our bodies. This can make 0-5°C feel colder and more uncomfortable than a drier cold temperature like -15/-20°C with lower humidity.
Thermal Conductivity of Materials: Different materials have varying thermal conductivities, which determine their ability to transfer heat. For example, metals are good conductors of heat, and if you come into direct contact with a metal surface at 0-5°C, it can quickly draw heat away from your body, making it feel colder. On the other hand, materials like clothing or insulation with lower thermal conductivity can provide better insulation and reduce heat loss, making -15/-20°C feel less cold.
Psychological Factors: Perception of temperature is subjective and can be influenced by individual experiences and expectations. If you are mentally prepared for extremely cold temperatures like -15/-20°C, you may have a different perception and may be better equipped with appropriate clothing and mindset. However, if you are not expecting 0-5°C to be as cold or are dressed inadequately for the conditions, it may feel colder in comparison.
It's important to note that these factors can vary from person to person, and individual tolerance to cold temperatures may differ. Additionally, these explanations may not apply universally and can depend on specific environmental conditions and personal factors.