Travelling from most locations, it is best to book your flight to Denver during the month of November for the best deal, although there are other times of the year which offer great deals as well.
In general, most flyers find the cheapest time to book a flight to Denver is about 60 days prior.
In general, booking your departure to Denver for a Tuesday represents the best deal on airfare. Try to avoid a Sunday departure to stay away from the highest prices.
On average you can find the best deals on plane tickets to Denver when looking for flights with evening departure times.