An experiment was carried out during winter seasons of 2005-06, 2006-07 and 2007-08 at the Bidhan Chandra Krishi Viswavidyalaya, West Bengal, India with five wheat varieties (PBW 343, HD2733, HW 2045, PBW533 and K9107) on three dates of sowing (18th November, 3rd December and 18th December) in a split plot design, keeping dates of sowing in the main plot and varieties in the subplot with the objective to find out the effect of temperature change on the duration of different phenophases of wheat crop and its productivity. The phenophases (CRI, tillering, flowering and milk) were delineated and the duration of exposure of the crop to higher maximum and minimum temperature than the normal and extent of high temperature were worked out. The 18th November sown crop had to tolerate a higher maximum and minimum temperature than their normal to the tune of 2o and 3.5o C respectively. When the sowing was delayed the crop was exposed to more maximum and minimum temperature than the earlier sown crops. On second date, the crop had to tolerate a 3.9 and 5.3oC more maximum and minimum temperatures than their normal values. The December sown crop was also exposed to higher maximum and minimum temperature than the normal values. Ear weight at the milk stage could be significantly explained through the variation in cumulative maximum as well as minimum temperatures at the flowering stage. The cumulative maximum temperature (as predictor) explained 20% variation in ear weight at the milk stage whereas 15% variation was explained through the cumulative minimum temperature for the same phenophase. The cumulative minimum temperature at the flowering stage explained 20% variation in LAI significantly.