The capital Dhaka, along with the rest of the country, is currently experiencing moderate to severe heatwaves.
The Meteorology Department has extended the heat alert for another 72 hours, starting Thursday morning, with the possibility of further extension.
These alerts are issued when there's a widespread occurrence of heatwaves.
With the scorching heat causing extreme discomfort, the Meteorological Department predicts a further rise in temperatures nationwide, indicating that there would be no relief unless rainfall occurs.
Meanwhile, amidst the sweltering conditions, many are turning to Google to check the temperature across the country. However, a common query arises when viewing the temperature on Google.
While Google displays the temperature at the top for a specific area, just below it, in smaller font, it reads "Feels Like" along with another temperature.
For instance, at 4pm on Saturday, the temperature in Dhaka was shown 37°C, but the "feels like" temperature was 44°C.
Why are the two temperatures so dissimilar?
The "feels like" temperature indicates the actual sensation of heat or cold experienced outdoors. It is determined based on environmental factors such as air temperature, humidity levels, and wind speed, which collectively influence how the weather is perceived by individuals exposed to it.
Meteorologists explain that the "Feels Like" temperature refers to the perceived temperature in a particular area. This perceived temperature can be higher due to various environmental factors, regardless of the actual temperature.
To clarify further, the "Feels Like" temperature is what's sensed by the human body when the temperature reflected from the earth's surface interacts with it.
Furthermore, areas with more urbanization, such as higher vehicular traffic and industrial activities, tend to have a higher perceived temperature compared to rural areas with more greenery and water bodies.
While the perceived temperature is elevated during summer due to these factors, the opposite holds true during winter. Hence, even if the air temperature is 15°C during winter, it may "feel like" 10°C, indicating a colder sensation experienced by the residents.
Heat index
In the summer, the feels-like temperature is also called the heat index.
According to Fox Weather, the heat index is a measure of how hot the air feels when taking into account the combination of the air temperature and the relative humidity or dew point.
That means on a humid day in the summer, the heat index will be relatively higher than the actual air temperature.
Experts note that higher humidity levels delay the evaporation of sweat, making it harder for the body to cool down, thus increasing discomfort.
Wind chill
In the winter, the feels-like temperature is called the wind chill.
The wind chill is how cold the air feels on your skin when factoring in the wind for any temperature at or below 50 degrees with wind speeds above 3mph.
That means on a windy day in the winter, the wind chill will be notably lower than the actual air temperature.
A thin layer of warm air, produced by body heat, exists just above your skin. The wind strips this warmth away. As wind speeds increase, the amount of heat lost from your body also increases. Therefore, the stronger the winds, the colder the air will feel.
How is the 'feels like' temperature determined?
The “feels like” temperature is calculated by considering the forecasted air temperature, relative humidity, and wind speed at approximately five feet above the ground (typical face level), along with knowledge of how heat dissipates from the human body in cold and windy conditions.
On windy days, the rate of moisture evaporation from the skin increases, leading to heat being drawn away from the body, resulting in a sensation of colder temperatures than what is actually measured.
However, this effect diminishes as temperatures rise, with humidity playing a more significant role in warmer conditions.
During perspiration, the evaporation of sweat cools the body by removing heat. In high humidity, this process is hindered, causing the body to feel warmer than the measured temperature.
Utilizing these principles, a formula is applied to adjust the air temperature, accounting for wind chill at lower temperatures, heat index at higher temperatures, and a blend of both in intermediate conditions.
