State guide

Colorado Nature Guide

Colorado is a state of staggering vertical range, from the short-grass high plains in the east through the Front Range foothills to the alpine tundra above treeline in the Southern Rockies, and on to the warmer fruit valleys of the Western Slope. Its nature calendar is governed by altitude as much as by season — spring climbs the mountains week by week, the marquee event being the tens of thousands of sandhill cranes that stage in the San Luis Valley each March, and the year closes with the September spectacle of golden aspen sweeping the high country. Semi-arid, intensely sunny, and blessed with some of the darkest skies in the Lower 48, it rewards anyone willing to chase the season up and down the slopes.

519bird species
Lark Buntingstate bird
Rocky Mountain Columbinestate flower
Colorado Blue Sprucestate tree
3a–6bUSDA zones

Every month in Colorado

Explore by subject

The whole year

Get the complete Colorado Nature Year

Everything for a full year of nature in Colorado — all twelve monthly guides, a wall poster, the field checklist, and weekly email access, in one bundle.

Guide coming soon

Free weekly Colorado nature update

The weekly nature update is coming soon. Check back shortly — it lands here when it opens.