Here's when not to travel I-70 in the Colorado mountains

State of play: Looking at travel to five Colorado resorts shows January and February are the worst months along with March 18-29, according to an exclusive INRIX traffic analysis for Axios Denver.

• The busiest days of the week are easily Saturday and Sunday. 
• The day with the least traffic is Tuesday.

By the numbers: The bulk of the traffic congestion takes place on weekends between 11am and 4pm. Weekday traffic is similarly bad in the middle of the day.

Between the lines: The analysis looked at traffic to Breckenridge, Keystone, Vail, Winter Park and Steamboat.

• All resorts see crowds at similar times except Steamboat, where travelers tend to leave a day earlier — Friday — and the lightest traffic day is Sunday.

What they're saying: "Traffic is heaviest in January, especially around holidays and long weekends like Presidents Day," INRIX analyst Bob Pishue tells Axios. "And remember, these are not just skiers—it's employees, freight trucks, day-trippers and people just driving through."

• "The lightest days are almost at the tail end of the year when snow coverage is lighter, but diehards will stretch the season out as long as they can," added former Colorado ski bum turned INRIX spokesperson Mark Burfeind.