Round Valley Reservoir — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Round Valley Reservoir, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Round Valley Reservoir today is 20.6°C.
Water Temperature: Daily Trends, Historical Records, and Forecast
✅ As of today, the minimum water temperature ranges from 68°F (20°C) to 74°F (23°C). The water is warm and pleasant for swimming, and in this range, one can stay in the water for extended periods without the risk of hypothermia. This is the ideal temperature for relaxation, swimming, and water sports. Families with children, as well as outdoor enthusiasts, will enjoy swimming and time spent in the water. For most people, this is the optimal temperature for a comfortable beach experience. 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 |
|---|---|---|---|
| JUN 3 | 18.6°C | 22.5°C | |
| JUN 4 | 19.0°C | 22.5°C | |
| JUN 5 | 19.6°C | 22.5°C | |
| JUN 6 | 19.8°C | 22.5°C | |
| JUN 7 | 20.1°C | 22.5°C | |
| JUN 8 | 20.2°C | 22.5°C | |
| JUN 10 | 20.6°C | 22.5°C | |
| JUN 11 | 22.5°C | 20.7°C | |
| JUN 12 | 22.5°C | 20.8°C | |
| JUN 13 | 22.5°C | 20.9°C | |
| JUN 14 | 22.5°C | 21.0°C | |
| JUN 15 | 22.5°C | 21.1°C | |
| JUN 16 | 22.5°C | 21.2°C | |
| JUN 17 | 22.5°C | 21.3°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 | 4°C | 7°C |
| February | 0°C | 4°C | 7°C |
| March | 1°C | 5°C | 8°C |
| April | 8°C | 14°C | 20°C |
| May | 13°C | 18°C | 22°C |
| June | 15°C | 23°C | 30°C |
| July | 16°C | 25°C | 33°C |
| August | 21°C | 26°C | 31°C |
| September | 19°C | 22°C | 25°C |
| October | 11°C | 15°C | 19°C |
| November | 5°C | 9°C | 12°C |
| December | 2°C | 5°C | 7°C |
Round Valley Reservoir: Water Temperature by Location
Round Valley Reservoir: Weather Forecast
June 9
June 10
June 11
June 12
June 13
June 14
Location & Local Information
Round Valley Reservoir is a deep, glacially styled lake in New Jersey known for clear but cold water. Surface temperatures vary seasonally: in summer the surface typically warms to roughly 65–75°F (18–24°C) at peak, while late spring and early fall usually see 45–60°F (7–16°C). Winter surface readings commonly sit near or just above freezing, around 34–45°F (1–7°C). Because the reservoir is unusually deep, lower layers remain much colder year-round; temperatures below the thermocline can stay near 40°F (4–5°C) even in midsummer, so water near depth changes quickly and can be shockingly cold compared with the surface.
Swimming in Round Valley Reservoir is not permitted; the managing authorities restrict direct swimming for safety and operational reasons. Steep drop-offs, sudden depth changes, and very cold deep water increase the risk of hypothermia and underwater disorientation, while boat traffic and limited shoreline access raise further safety concerns. Those restrictions are intended to prevent accidents in an environment where surface warmth can be deceptive and where cold, deep water and terrain create hazardous conditions for casual swimmers.