The objective of the present study is to estimate the duration of extreme thermal bioclimate conditions in and around Kolkata, one of the highly densely populated cities in India. The biometeorological conditions have been calculated by Physiologically Equivalent Temperature (PET) using RayMan model at 0530 h and 1430 h (IST) based on meteorological data for the stations Kolkata (Alipore), Dum Dum and Diamond Harbour for the period January, 2020 to December, 2021. Dum Dum is located to the north of Kolkata and Diamond Harbour is situated to the south of Kolkata. The meteorological data have been retrieved from the station data measured by Indian Meteorological Department (IMD). The atmospheric variables required to calculate the PET index are air temperature, relative humidity, cloud cover and wind speed. A recent study reported that stations outside Kolkata suffer warmer human thermal stress conditions. To account for the prolonged thermal stress periods, PET with greater than 40 ° C is categorized as an episode if it turns up consecutively for more than 5 days. The results from this analysis computes no such event in any of the investigated stations at 0530 h (IST). At 1430 h, the frequency of occurrences of PET with > 40 ° C for the period between 5 to 10 days is 12 for Diamond Harbour followed by Dum Dum (5) and Kolkata (3). Similar pattern is observed when the frequency is calculated for the duration between 11-20 days. The frequency of such duration is 6, 3, 2 for Diamond Harbour, Dum Dum, Kolkata respectively.