How the COLDERBolder 5K Race Structure Works

The COLDERBolder 5K is built around 14 races plus one walking wave: 13 invitational races organized by pace, one open race for anyone who doesn't qualify for an invitational or just wants a casual day, and a non-competitive walking wave. You only get into an invitational race by email invitation, which goes to people who ran a previous COLDERBolder or the BOLDERBoulder. Registration opens to the public on October 1st, and there is no race-day registration — the event sells out every year.

The three ways to take part

1. The 13 invitational races

These are the competitive core of the event, and they are organized by pace rather than by age group or gender.

• Who gets in: Runners who finished the 2025 COLDERBolder or the 2026 BOLDERBoulder receive an invitation by email. If you ran either event, watch your inbox rather than the public registration page.
• How the pace grouping works: You race only against people who finished at a similar speed. The example given on the site: if you ran the BOLDERBoulder in 52 minutes, your race includes only people who finished between 52:00 and 53:59.
• What's at stake: Everyone who finishes earns a medal, but the top 3 finishers in each invitational race earn a special Cold Medal.

The practical effect is that a mid-pack runner isn't racing against the front of the field — you're racing against your own pace cohort, which is what the site means by "everyone has a fair shot at racing glory."

2. The open race

The open race exists for two kinds of people:

• Those who don't qualify for an invitational race (for example, you haven't run a previous COLDERBolder or BOLDERBoulder).
• Those who qualify but want a more relaxed race day.

You run at your own pace, and the site explicitly frames it as a chance to participate alongside friends or family. If your goal is to run with a group of mixed abilities, this is the wave that allows it.

3. The walking wave

The walking wave is a festive stroll through the CU campus winter setting, not a race. There are no 1st, 2nd, or 3rd place Cold Medals, but all participants receive a medal.

Quick comparison

What the $66 package includes

The site lists the following for the $66 package:

• Official COLDERBolder shirt and winter beanie
• Race medal (after completing your 5K)
• Official COLDERBolder bib with RFID timing tag
• Holiday Finish Fest: burritos, doughnuts, coffee, hot cocoa, and more

Virtual registration is also available. The site states there are no hidden fees.

Key logistics to plan around

• Date and location: Saturday, December 5th, on the CU campus.
• Registration timing: Public registration opens October 1st. Invited runners are contacted by email beforehand.
• No race-day signup: There is no race-day registration, and the event sells out every year — so the decision point is well before race week.
• If you can't make it: If you sign up and can't participate, you can roll your registration to next year for $30.

How to decide which wave fits you

• You ran a previous COLDERBolder or BOLDERBoulder: Check your email for the invitation, then decide between your pace-grouped invitational race and the open race. Choose the invitational if you want to race your speed cohort; choose the open if you'd rather run with friends or family at a relaxed pace.
• You haven't run either event: The open race is your entry point, unless you'd prefer the walking wave.
• You want the event experience without competition: The walking wave gets you the campus route, the Finish Fest, and a medal with no placement pressure.
• You can't travel to Boulder: Virtual registration is the option the site offers.