Keystone Lake — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Keystone Lake, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Keystone 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 | 17.5°C | 20.0°C | |
| JUN 4 | 17.7°C | 20.0°C | |
| JUN 5 | 18.6°C | 20.0°C | |
| JUN 6 | 19.0°C | 20.0°C | |
| JUN 7 | 19.9°C | 20.0°C | |
| JUN 8 | 20.4°C | 20.0°C | |
| JUN 10 | 21.0°C | 20.0°C | |
| JUN 11 | 20.0°C | 21.2°C | |
| JUN 12 | 20.0°C | 21.2°C | |
| JUN 13 | 20.0°C | 21.1°C | |
| JUN 14 | 20.0°C | 21.0°C | |
| JUN 15 | 20.0°C | 21.0°C | |
| JUN 16 | 20.0°C | 20.9°C | |
| JUN 17 | 20.0°C | 20.8°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 | 3°C | 6°C |
| February | 0°C | 4°C | 7°C |
| March | 1°C | 6°C | 11°C |
| April | 7°C | 12°C | 17°C |
| May | 11°C | 17°C | 22°C |
| June | 15°C | 20°C | 25°C |
| July | 23°C | 25°C | 27°C |
| August | 22°C | 26°C | 29°C |
| September | 20°C | 23°C | 25°C |
| October | 13°C | 17°C | 20°C |
| November | 5°C | 11°C | 17°C |
| December | 1°C | 5°C | 8°C |
Keystone Lake: Water Temperature by Location
Keystone Lake: Weather Forecast
June 9
June 10
June 11
June 12
June 13
Location & Local Information
Keystone Lake in Pennsylvania follows the seasonal temperature patterns typical of small temperate reservoirs. In winter months the surface often hovers just above freezing, roughly 32–40°F (0–4°C) and can be ice-covered at times. Spring brings a steady rise, with surface temperatures commonly in the 40–60°F (4–15°C) range as the lake mixes and warms. Peak summer temperatures are usually reached between June and August, when surface waters commonly warm to about 68–78°F (20–26°C) and occasionally into the low 80s°F (27–28°C) on very hot, calm days. During autumn the lake cools back down, with surface readings typically falling to 50–65°F (10–18°C) before winter sets in. Deeper water remains cooler year-round and thermal stratification in summer can lead to colder conditions below the surface.
Swimming is generally possible during the warmer months when surface temperatures are comfortable, but it is allowed only where local rules, signage and safety conditions permit. Access may be limited to designated swim areas to keep bathers away from boat traffic and submerged hazards. Authorities may close swimming temporarily for public-health reasons such as harmful algal blooms, high bacterial counts, or poor weather, and ice on the lake in winter makes swimming unsafe. Always follow posted rules and recent water-quality advisories before entering the water.