Windsor, CO has a population of 21,154 and is the 2,057th largest city in the United States. The population density is 865 per sq mi which is 1638% higher than the Colorado average and 855% higher than the national average. The median age in Windsor is 39 which is approximately 7% higher than the Colorado average of 36. In Windsor, 68% of the population over 15 years of age are married, 95% speak English and 2% speak Spanish. 46% of Windsor residents were born in Colorado, 51% were born out of state, 1% were born outside of the United States and 2% were foreign born.