The 3rd season starts on Oct 31st in 2009. Season structure in CO is set for five years at a time, with the current plan ending in 2009. They use the following parameters to determine starting dates for the rifle seasons.
Parameters for season dates
The Wildlife Commission will continue to utilize the following guidelines in development of the biggame season structure for the years 2005-2009:
A. Female animals are not hunted earlier than the last week of August.
B. Regular rifle seasons begin no earlier than the first Saturday after October 9.
C. Regular rifle seasons do not extend beyond mid-November.
By using the "first Saturday after Oct. 9" guideline, you should be able to predict when future rifle seasons will start, assuming that the new 5-year plan beginning in 2010 uses the same structure.