Flat River Reservoir — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Flat River Reservoir, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Flat River Reservoir today is 16.5°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
Table of Daily Sea Temperature Data
| Date | Current | Average | Forecast |
|---|---|---|---|
| OCT 5 | 19.3°C | 15.5°C | |
| OCT 6 | 18.2°C | 15.5°C | |
| OCT 7 | 18.9°C | 15.5°C | |
| OCT 8 | 18.0°C | 15.5°C | |
| OCT 9 | 16.9°C | 15.5°C | |
| OCT 10 | 17.4°C | 15.5°C | |
| OCT 11 | 17.1°C | 15.5°C | |
| OCT 12 | 17.4°C | 15.5°C | |
| OCT 13 | 15.5°C | 16.5°C | |
| OCT 14 | 15.5°C | 16.4°C | |
| OCT 15 | 15.5°C | 16.4°C | |
| OCT 16 | 15.5°C | 16.3°C | |
| OCT 17 | 15.5°C | 16.3°C | |
| OCT 18 | 15.5°C | 16.2°C | |
| OCT 19 | 15.5°C | 16.2°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 | 2°C | 4°C |
| February | 0°C | 2°C | 4°C |
| March | 0°C | 4°C | 7°C |
| April | 4°C | 10°C | 15°C |
| May | 11°C | 15°C | 20°C |
| June | 12°C | 18°C | 22°C |
| July | 21°C | 26°C | 31°C |
| August | 20°C | 25°C | 29°C |
| September | 18°C | 24°C | 29°C |
| October | 12°C | 16°C | 19°C |
| November | 4°C | 9°C | 13°C |
| December | 0°C | 3°C | 6°C |
Flat River Reservoir: Water Temperature by Location
Flat River Reservoir: Weather Forecast
October 13
October 14
October 15
October 16
October 17
Location & Local Information
Flat River Reservoir’s surface water temperatures follow the typical seasonal pattern for small New England impoundments. In spring the reservoir commonly ranges from about 45–65°F (7–18°C) as the water warms after ice-out. By summer, surface readings often reach roughly 70–80°F (21–27°C) on warm afternoons, while mid- to late-summer heat can push the shallowest areas toward the upper part of that range. In fall the surface cools again to roughly 50–68°F (10–20°C) and by winter the water near the surface approaches freezing, typically around 32–40°F (0–4°C) with ice forming in sustained cold spells. Deeper water remains cooler year-round, and temperature can vary with time of day, recent weather, and wind-driven mixing.
Swimming at Flat River Reservoir is possible in accessible areas during warmer months and many visitors swim there in summer, but local rules and safety considerations matter. Some parts of reservoirs are posted against swimming to protect drinking-water intakes, fragile shorelines, or for public-safety reasons such as boat traffic, underwater hazards, or cold-water shock outside summer. Water quality (including occasional algal blooms) can also affect whether swimming is advisable, so it’s best to heed posted signs and town or water-authority guidance before entering the water.