Colorado — Water Temperature Today and Throughout the Year

Water Temperature in Lakes and Rivers

Popular Lakes

Popular Rivers

Popular Places

Water Temperature and Swimming Overview

Water Temperature Trends

Colorado is known for its mountainous terrain, which directly impacts the water temperatures in its rivers and lakes. The state's high elevation means that many of its rivers and lakes receive water from snowmelt, keeping the water relatively cool even during the summer months. In rivers such as the Colorado River and the Arkansas River, water temperatures can be chilly throughout much of the year. In spring and summer, temperatures in these rivers can range from 50°F to 65°F (10°C to 18°C), depending on the location and time of year. These temperatures are perfect for activities like white-water rafting, kayaking, and fishing, although swimming can be quite brisk for those unaccustomed to cooler water.

Lakes in Colorado, especially those in the mountain regions, also experience significant seasonal fluctuations in water temperatures. For example, in Lake Dillon, located in the Rockies, water temperatures can hover around 50°F to 60°F (10°C to 16°C) during the summer, making it an ideal spot for boating and fishing, though it may be too cold for long swims. As fall sets in, water temperatures can drop to around 40°F to 50°F (4°C to 10°C), making swimming less enjoyable and limiting the opportunities for water activities. In contrast, larger reservoirs like Cherry Creek Reservoir in the Denver area can warm up more during the summer months, reaching temperatures of 70°F to 75°F (21°C to 24°C), which is more comfortable for swimming and recreational activities.

In Colorado’s higher-altitude lakes, like those found in Rocky Mountain National Park, the water remains much colder, typically ranging from 40°F to 50°F (4°C to 10°C) even in summer. These cool temperatures are due to the deep and pristine mountain lakes that are often fed by snowmelt from the surrounding peaks. While these lakes are beautiful and provide excellent opportunities for fishing, they are generally too cold for comfortable swimming, except perhaps for those seeking an invigorating dip. In the winter, water temperatures in most rivers and lakes drop significantly, often falling below freezing in areas where water flow slows or stops, especially in mountain streams.