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Lake Sinai — Current Water Temperature, Annual Trends and Forecast

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

Big Stone Lake, United States
Big Stone Lake, United States © By McGhiever, CC BY-SA 3.0

Current Water Temperature

27.2°C
Today
25.8°C
Yesterday
23.3°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 Sinai today is 27.2°C.

Water Temperature: Daily Trends, Historical Records, and Forecast

✅ As of today, the minimum water temperature ranges from 79°F (26°C) to 82°F (28°C). This is very warm water, allowing for extended stays without any discomfort. Swimming in these conditions will be particularly enjoyable, making it the ideal temperature range for those who want to relax in the sea. Additionally, water in this temperature range is suitable for children and elderly people, as it is comfortable for prolonged stays. 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 June 20 to July 21

Table of Daily Sea Temperature Data

Date Current Average Forecast
JUL 1423.3°C22.1°C
JUL 1525.5°C22.1°C
JUL 1625.5°C22.1°C
JUL 1725.7°C22.1°C
JUL 1825.7°C22.1°C
JUL 1925.8°C22.1°C
JUL 2025.8°C22.1°C
JUL 2125.3°C22.1°C
JUL 2222.1°C26.9°C
JUL 2322.1°C26.7°C
JUL 2422.1°C26.4°C
JUL 2522.1°C26.2°C
JUL 2622.1°C25.9°C
JUL 2722.1°C25.7°C
JUL 2822.1°C25.4°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
January0°C6°C12°C
February0°C8°C15°C
March1°C9°C17°C
April3°C12°C20°C
May7°C15°C23°C
June15°C19°C24°C
July17°C22°C28°C
August20°C24°C28°C
September17°C20°C22°C
October5°C12°C19°C
November3°C7°C10°C
December0°C5°C8°C

Lake Sinai: Water Temperature by Location

Lake Sinai: Weather Forecast

July 22

° / °
overcast
rain: 1% | wind:

July 23

° / °
light drizzle
rain: 3% | wind:

July 24

° / °
moderate rain
rain: 23% | wind:

July 25

° / °
fog
rain: 2% | wind:

July 26

° / °
partly cloudy
rain: 7% | wind:

Location & Local Information

Lake Sinai, like many small prairie lakes in South Dakota, experiences pronounced seasonal swings in surface water temperature. In spring the surface typically warms from roughly 40–60°F (4–15°C) as thaw and runoff progress. Summer surface temperatures commonly reach about 68–80°F (20–27°C) on warm days, and can briefly exceed that during heat waves. In autumn the water cools back to around 45–65°F (7–18°C) before winter settles in; during winter the lake surface often approaches the freezing point, about 32°F (0°C), and will form ice layers so open water temperatures are at or just above freezing beneath the ice.

Swimming at Lake Sinai is generally an activity pursued during the warmer months where public access and beaches exist, but specific permissions depend on local management and posted rules. Recreational swimming is often allowed because the lake is used for boating and fishing as well, yet there may be no lifeguards, and water quality can vary seasonally with algal blooms, runoff after rains, or low clarity that affect safety. For those considering a swim, confirm current advisories, obey signage, and be mindful of cold-water risks early and late in the season, since temperatures below about 70°F (21°C) can feel uncomfortable and increase hypothermia risk with prolonged exposure.

Nearby Lakes

Frequently Asked Questions

What is the current water temperature in Lake Sinai?
Water Temperature in Lake Sinai today is 27.2°C.
What is the water temperature in Lake Sinai during the summer months?
The water temperature in Lake Sinai in summer fluctuates in the range of 15°C - 28°C.
Is it possible to swim in Lake Sinai and what are the possibilities for this?
Lake Sinai in South Dakota is a popular location for water activities, hence swimming is possible. The suitability for swimming, however, is subjective and depends on the water temperature, weather, and individual's swimming ability.