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.
Current Water Temperature
Water Temperature in Lake Oahe today is 18.5°C.
Water Temperature: Daily Trends, Historical Records, and Forecast
⚠️ As of today, the minimum water temperature ranges from 65°F (18°C) to 68°F (20°C). This is already quite warm water, which is ideal for most people. Swimming becomes comfortable, and prolonged stays in the water do not cause discomfort. This temperature is perfect for family trips and for those who prefer warmer water. It is also comfortable for water sports such as surfing or swimming. 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
Table of Daily Sea Temperature Data
| Date | Current | Average | Forecast |
|---|---|---|---|
| SEP 14 | 19.7°C | 21.0°C | |
| SEP 15 | 18.8°C | 21.0°C | |
| SEP 16 | 18.9°C | 21.0°C | |
| SEP 17 | 18.4°C | 21.0°C | |
| SEP 18 | 18.0°C | 21.0°C | |
| SEP 19 | 18.0°C | 21.0°C | |
| SEP 20 | 18.4°C | 21.0°C | |
| SEP 21 | 18.5°C | 21.0°C | |
| SEP 22 | 21.0°C | 18.6°C | |
| SEP 23 | 21.0°C | 18.8°C | |
| SEP 24 | 21.0°C | 18.9°C | |
| SEP 25 | 21.0°C | 19.0°C | |
| SEP 26 | 21.0°C | 19.1°C | |
| SEP 27 | 21.0°C | 19.3°C | |
| SEP 28 | 21.0°C | 19.4°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 |
|---|---|---|---|
| January | 0°C | 6°C | 12°C |
| February | 0°C | 8°C | 15°C |
| March | 1°C | 9°C | 17°C |
| April | 3°C | 12°C | 20°C |
| May | 8°C | 15°C | 22°C |
| June | 16°C | 19°C | 23°C |
| July | 17°C | 23°C | 29°C |
| August | 21°C | 25°C | 28°C |
| September | 18°C | 21°C | 24°C |
| October | 5°C | 12°C | 18°C |
| November | 4°C | 7°C | 10°C |
| December | 1°C | 6°C | 11°C |
Lake Oahe: Water Temperature by Location
Lake Oahe: Weather Forecast
September 21
September 22
September 23
September 24
September 25
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.