Blue Marsh Lake — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Blue Marsh Lake, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Blue Marsh Lake today is 21.3°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 | 17.2°C | 17.5°C | |
| JUN 4 | 17.9°C | 17.5°C | |
| JUN 5 | 18.5°C | 17.5°C | |
| JUN 6 | 18.8°C | 17.5°C | |
| JUN 7 | 20.0°C | 17.5°C | |
| JUN 8 | 20.6°C | 17.5°C | |
| JUN 11 | 17.5°C | 21.1°C | |
| JUN 12 | 17.5°C | 20.9°C | |
| JUN 13 | 17.5°C | 20.7°C | |
| JUN 14 | 17.5°C | 20.5°C | |
| JUN 15 | 17.5°C | 20.4°C | |
| JUN 16 | 17.5°C | 20.2°C | |
| JUN 17 | 17.5°C | 20.0°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 | 2°C | 6°C | 10°C |
| April | 7°C | 12°C | 16°C |
| May | 13°C | 18°C | 23°C |
| June | 13°C | 18°C | 22°C |
| July | 20°C | 25°C | 29°C |
| August | 21°C | 23°C | 26°C |
| September | 20°C | 23°C | 26°C |
| October | 12°C | 18°C | 24°C |
| November | 6°C | 11°C | 16°C |
| December | 2°C | 6°C | 10°C |
Blue Marsh Lake: Water Temperature by Location
Blue Marsh Lake: Weather Forecast
June 9
June 10
June 11
June 12
Location & Local Information
Blue Marsh Lake, a reservoir in southeastern Pennsylvania, experiences a wide seasonal range in surface water temperature. In winter the surface commonly approaches freezing, roughly 32–40°F (0–4°C). Spring brings a steady rise, with surface values typically between about 40 and 65°F (4–18°C) as weather moderates and inflows warm. In summer the upper layers often warm into the upper 60s to low 80s Fahrenheit, about 20–28°C, especially on sunny, calm days; deeper water remains much cooler due to stratification. By autumn the lake cools again, with surface temperatures generally falling into the 50–65°F range (10–18°C) before the lake mixes toward winter. Actual temperatures vary day-to-day with air temperature, sunlight, stream inflows and reservoir depth, so local readings can differ from these general seasonal bands.
Swimming in Blue Marsh Lake is restricted. The U.S. Army Corps of Engineers and local authorities generally prohibit bathing and unsupervised swimming in the reservoir because of safety concerns, including changing currents, boat traffic, cold deep water, submerged hazards and the absence of lifeguards. Those factors, together with occasional water-quality issues in parts of the watershed, are why open-water swimming is not permitted on most of the lake despite its recreational use for boating, fishing and shoreline activities.