Idaho — 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

In Idaho, water temperatures in rivers and lakes vary greatly depending on the location and time of year. In the warmer months, many rivers such as the Snake River, Salmon River, and Clearwater River experience water temperatures ranging from 50°F to 65°F (10°C to 18°C). These temperatures are ideal for activities like rafting, kayaking, and fly fishing, as the cool waters offer refreshing relief from the summer heat. The Snake River, for example, reaches temperatures in this range during late spring and summer, creating a pleasant environment for outdoor enthusiasts. However, the water can still be quite chilly, especially in the early mornings or in higher-altitude regions.

In contrast, during the colder months, particularly in winter, the water temperatures in Idaho’s rivers can drop significantly. In areas like the Salmon River and Clearwater River, the water temperature can fall to around 32°F to 40°F (0°C to 4.5°C). Such low temperatures make recreational activities like swimming and boating dangerous, and often, the rivers can freeze in parts, especially in the more northern and higher elevation regions. The water temperature in these conditions is not suitable for water sports, and the focus shifts to winter activities like snow sports in the nearby mountains.

Idaho's lakes also experience a wide range of water temperatures. In the summer months, lakes like Lake Pend Oreille and Bear Lake have temperatures that hover around 65°F to 75°F (18°C to 24°C), making them popular spots for boating, swimming, and fishing. These temperatures are perfect for a refreshing swim, and the crystal-clear waters of these lakes provide excellent visibility for those who enjoy diving or snorkeling. In the winter, temperatures in these lakes drop significantly, often dipping below 40°F (4.5°C), which makes swimming or other water activities uncomfortable and unsafe. During the colder months, ice fishing becomes more common as the lakes freeze over in some areas.