Sunnyside Reservoir — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Sunnyside Reservoir, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Sunnyside Reservoir today is 17.3°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 |
|---|---|---|---|
| SEP 15 | 18.2°C | 21.0°C | |
| SEP 16 | 19.0°C | 21.0°C | |
| SEP 17 | 18.5°C | 21.0°C | |
| SEP 18 | 18.4°C | 21.0°C | |
| SEP 19 | 18.5°C | 21.0°C | |
| SEP 20 | 17.7°C | 21.0°C | |
| SEP 21 | 18.4°C | 21.0°C | |
| SEP 22 | 18.0°C | 21.0°C | |
| SEP 23 | 21.0°C | 17.5°C | |
| SEP 24 | 21.0°C | 17.7°C | |
| SEP 25 | 21.0°C | 17.9°C | |
| SEP 26 | 21.0°C | 18.0°C | |
| SEP 27 | 21.0°C | 18.2°C | |
| SEP 28 | 21.0°C | 18.4°C | |
| SEP 29 | 21.0°C | 18.6°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 | 3°C | 7°C | 10°C |
| February | 4°C | 8°C | 11°C |
| March | 6°C | 10°C | 13°C |
| April | 9°C | 13°C | 17°C |
| May | 11°C | 17°C | 22°C |
| June | 14°C | 22°C | 28°C |
| July | 19°C | 24°C | 29°C |
| August | 18°C | 23°C | 28°C |
| September | 16°C | 21°C | 26°C |
| October | 11°C | 15°C | 19°C |
| November | 5°C | 10°C | 13°C |
| December | 4°C | 8°C | 11°C |
Sunnyside Reservoir: Water Temperature by Location
Sunnyside Reservoir: Weather Forecast
September 23
September 24
September 25
September 26
September 27
Location & Local Information
#Surrey
Sunnyside Reservoir in Surrey experiences the sort of seasonal water temperatures typical of lowland English reservoirs. In winter the surface tends to sit around 4–8 °C (39–46 °F), rising in spring to roughly 8–14 °C (46–57 °F) as the water stratifies. Summer can bring the warmest readings, commonly 15–22 °C (59–72 °F) on the surface during prolonged warm spells, while autumn sees cooling back to about 9–14 °C (48–57 °F). These figures are approximate and can vary with weather, depth and water turnover: deeper or shaded parts stay noticeably colder than the surface.
Swimming at Sunnyside Reservoir is generally not permitted because it functions as a managed waterbody where safety and water quality are priorities. Restrictions reflect risks such as cold-water shock, hidden currents and depth changes, plus the need to protect the reservoir as part of local water infrastructure. Instead, the site and surrounding area are used for quieter pursuits: there are pleasant riverside and reservoir-side walks, good opportunities for birdwatching and informal cycling, and nearby Surrey villages and green spaces offer pubs, historic buildings and further countryside routes to explore.