An experiment laid out in simple RBD combined over dates of sowing (22nd Feb–D1 , 7th March–D2 and 22nd March–D3 ) and varieties (V1 –BT-894-3, V2 –Rama and V3 –BT-893-1) was carried out in three successive years (2004, 2005 and 2006) at BCKV, W. B. to find out temperature and humidity profile within sesamum canopy and their impact on various growth processes. Results revealed that different dates of sowing exposed the crop to different ranges of temperature and RH (above and below the crop). From PCR analysis it is evident that temperature and RH on all data points significantly affected the biometric parameters. This crop could not be sown after 7th March under West Bengal condition; both the flowering and capsule-setting would be adversely affected by higher temperature below the sesamum canopy.