Patna: Residents across Bihar are grappling with sweltering conditions as a combination of high temperatures and rising humidity makes the weather feel significantly hotter than official temperature readings suggest.
Meteorologists have warned that people should not rely solely on maximum temperature figures when assessing heat-related risks, pointing instead to the heat index — a measure of how hot conditions actually feel to the human body.
On Tuesday, Patna recorded a maximum temperature of 41.3°C. However, according to data from the Patna Meteorological Centre, the heat index in the city climbed to around 48°C, indicating a much higher level of discomfort.
A similar trend was observed in Gaya, where the maximum temperature reached 41.4°C while the heat index stood at 44.9°C.
Heat Index Highlights Human Discomfort
The Meteorological Centre has begun including heat index figures alongside temperature and relative humidity data in its regular weather reports.
Officials say the heat index provides a more accurate picture of the conditions experienced by people, as it factors in humidity levels in addition to air temperature.
The resulting gap between actual temperatures and perceived temperatures has become increasingly noticeable across many districts, contributing to greater discomfort and heat stress.
Meteorologists have advised residents to plan outdoor activities according to the conditions they actually experience rather than relying solely on thermometer readings.
— Mausam Bihar- IMD Patna (@imd_patna) June 9, 2026
Why Humidity Makes Heat Worse
According to officials, the heat index is calculated using a combination of maximum temperature and relative humidity, while wind conditions can also influence how heat is perceived.
Meteorologists said humidity plays a critical role in determining how hot conditions feel.
When body temperature rises, the human body naturally produces sweat to cool itself. The cooling effect occurs when sweat evaporates from the skin.
However, during periods of high humidity, the atmosphere already contains a large amount of moisture, reducing the rate at which sweat can evaporate. As a result, the body’s natural cooling mechanism becomes less effective.
This causes people to experience greater discomfort and increases the risk of heat-related illnesses.
Experts note that the impact of heat can vary depending on factors such as age, health conditions, humidity levels and wind speed.
Cities Emerging As Heat Islands
Meteorologists also point to the growing urban heat island effect as a factor contributing to rising discomfort in cities.
Large expanses of concrete and built-up infrastructure absorb and retain heat, reducing the cooling influence of natural airflow and vegetation.
In urban areas, buildings and paved surfaces can trap heat, creating noticeable temperature differences compared with surrounding rural regions.
Experts say the phenomenon is becoming increasingly visible in Bihar’s cities and is being compounded by broader climatic changes.
Call For Greater Caution
With temperatures continuing to exceed 40°C in several parts of the state, weather officials have urged residents to remain cautious, stay hydrated and avoid prolonged exposure to direct sunlight during peak afternoon hours.
The Meteorological Centre stressed that the heat index should be treated as an important indicator of heat stress, particularly during periods of high humidity when the weather may feel far more severe than the recorded temperature suggests.
