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Lake Oahe — Current Water Temperature, Annual Trends and Forecast

This page provides information on the current water temperature in Lake Oahe, trends, monthly ranges and the forecast for the coming days.

Merritt Reservoir, United States
Merritt Reservoir, United States © By Ammodramus, CC0

Current Water Temperature

15.5°C
Today
14.2°C
Yesterday
16.8°C
A Week Ago
Get instant access to real-time water temperatures for this and all other locations with our iOS and Android apps.

Water Temperature in Lake Oahe today is 15.5°C.

Water Temperature: Daily Trends, Historical Records, and Forecast

⚠️ As of today, the minimum water temperature ranges from 60°F (15°C) to 65°F (18°C). The water is comfortable for most people, making it an ideal range for water sports enthusiasts. The temperature does not cause significant discomfort, and swimming will be pleasant for the majority. However, it's important to remember that prolonged exposure to the water can still lead to cooling, so it's essential to monitor the time spent in the water, especially for children or elderly people. It is important to note that these swimming tips and recommendations apply only in good weather. When the air temperature is below 68°F (20°C), and sometimes even below 77°F (25°C), swimming can be unpleasant even with relatively high water temperatures.

Water Temperature Chart Over the Last 30 Days

From September 12 to October 13

Table of Daily Sea Temperature Data

Date Current Average Forecast
OCT 516.8°C11.5°C
OCT 615.8°C11.5°C
OCT 715.3°C11.5°C
OCT 815.7°C11.5°C
OCT 915.5°C11.5°C
OCT 1015.2°C11.5°C
OCT 1114.2°C11.5°C
OCT 1214.8°C11.5°C
OCT 1311.5°C15.3°C
OCT 1411.5°C15.1°C
OCT 1511.5°C14.9°C
OCT 1611.5°C14.7°C
OCT 1711.5°C14.5°C
OCT 1811.5°C14.3°C
OCT 1911.5°C14.1°C

* Current - Actual water temperature value

** Average - Average water temperature on this day in recent years

*** Forecast - Our water temperature forecast

Actual nearshore water temperatures may fluctuate by several degrees from the reported values, especially following heavy rainfall or extended periods of strong winds. Certain wind patterns can cause colder, deeper waters to rise and replace the sun-warmed surface water, leading to noticeable variations.

Our forecast is based on a proprietary mathematical model that considers real-time water temperature changes, historical trends, key weather patterns, wind strength and direction, and air temperature specific to each region. Additionally, we incorporate data from other resorts to enhance accuracy.

Monthly Water Temperature Range (Min, Max & Average)

Month Min Avg Max
January0°C6°C12°C
February0°C8°C15°C
March1°C9°C17°C
April3°C12°C20°C
May8°C15°C22°C
June16°C19°C23°C
July17°C23°C29°C
August21°C25°C28°C
September18°C21°C24°C
October5°C12°C18°C
November4°C7°C10°C
December1°C6°C11°C

Lake Oahe: Water Temperature by Location

Lake Oahe: Weather Forecast

October 13

° / °
light drizzle
rain: 15% | wind:

October 14

° / °
light drizzle
rain: 18% | wind:

October 15

° / °
slight rain
rain: 41% | wind:

October 16

° / °
overcast
rain: 23% | wind:

October 17

° / °
mainly clear
snow: 2% | wind:

Location & Local Information

Lake Oahe is a large Missouri River reservoir in South Dakota with surface water temperatures that follow the northern Plains’ seasonal cycle. In spring the lake often runs cool, typically about 40–60°F (4–16°C) as snowmelt and spring runoff dominate. Summer surface temperatures commonly rise into the mid-60s to upper 70s, roughly 65–80°F (18–27°C) in the warmest months, especially in shallow bays and along sandy shorelines. In autumn the water cools again to roughly 50–65°F (10–18°C), and by winter much of the surface approaches freezing, often around 32–40°F (0–4°C) with ice forming in protected coves and shallows.

Swimming is generally permitted at many of Lake Oahe’s designated recreation sites and public beaches because the reservoir is managed for multiuse recreation, but conditions vary and caution is advised. Designated swimming areas may lack lifeguards and water quality or safety advisories can be issued for algal blooms, debris, strong currents near the dam, boat traffic, and sudden drop-offs. Cold water temperatures outside the midsummer window increase hypothermia risk, so swimmers should choose marked areas, heed posted warnings, and be mindful of boat zones and weather-driven waves when deciding to enter the water.

Nearby Lakes

Frequently Asked Questions

What is the current water temperature in Lake Oahe?
Water Temperature in Lake Oahe today is 15.5°C.
What is the water temperature in Lake Oahe during the summer months?
The water temperature in Lake Oahe in summer fluctuates in the range of 16°C - 29°C.
Is it possible to swim in Lake Oahe and what are the possibilities for this?
Yes, it is possible to swim in Lake Oahe, South Dakota. The lake is open for numerous recreational activities including swimming, but official swimming areas or facilities may not be available.