Based on experimental data from COBOR for the years of 1991- 2005 relating to three earliness groups of corn the authors determined the dates of sowing, harvest, as well as selected growing stages. Using WGENK model, 300 possible variants of the course of weather were generated according to the scenario of the GISS model E with double CO2 in atmosphere. According to implemented calculations on stimulation database, growth season will decrease, on average, from 230 to 261 days. Probable deadline of its beginning might be 4th of March while ending might be 20th of November. Possible mean deadline of sowing of corn is 1st of April and harvest between 5th and 8th of August. According to generated data it is possible that the mean duration of the whole vegetation season of corn will decrease from 149 to 126 days for early variety, from 154 up to 128 for semi-early variety, and from 160 up to 129 for semi-late variety. All corn growing periods might decrease with the exception of the period between sprouting of stigma and full ripeness which might increase by about 20 days.