Thomas Hill Reservoir — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Thomas Hill Reservoir, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Thomas Hill Reservoir today is 18.7°C.
Water Temperature: Daily Trends, Historical Records, and Forecast
⚠️ As of today, the minimum water temperature ranges from 65°F (18°C) to 68°F (20°C). This is already quite warm water, which is ideal for most people. Swimming becomes comfortable, and prolonged stays in the water do not cause discomfort. This temperature is perfect for family trips and for those who prefer warmer water. It is also comfortable for water sports such as surfing or swimming. 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 | 20.8°C | 18.5°C | |
| OCT 6 | 20.1°C | 18.5°C | |
| OCT 7 | 20.1°C | 18.5°C | |
| OCT 8 | 19.7°C | 18.5°C | |
| OCT 9 | 20.0°C | 18.5°C | |
| OCT 10 | 19.3°C | 18.5°C | |
| OCT 11 | 19.3°C | 18.5°C | |
| OCT 12 | 19.0°C | 18.5°C | |
| OCT 13 | 18.5°C | 18.7°C | |
| OCT 14 | 18.5°C | 18.7°C | |
| OCT 15 | 18.5°C | 18.7°C | |
| OCT 16 | 18.5°C | 18.7°C | |
| OCT 17 | 18.5°C | 18.7°C | |
| OCT 18 | 18.5°C | 18.6°C | |
| OCT 19 | 18.5°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 | 0°C | 3°C | 6°C |
| February | 0°C | 4°C | 8°C |
| March | 3°C | 9°C | 16°C |
| April | 8°C | 14°C | 20°C |
| May | 14°C | 19°C | 25°C |
| June | 19°C | 23°C | 26°C |
| July | 25°C | 28°C | 31°C |
| August | 22°C | 26°C | 31°C |
| September | 22°C | 25°C | 28°C |
| October | 14°C | 19°C | 23°C |
| November | 4°C | 10°C | 16°C |
| December | 0°C | 3°C | 6°C |
Thomas Hill Reservoir: Water Temperature by Location
Thomas Hill Reservoir: Weather Forecast
October 13
October 14
October 15
October 16
October 17
October 18
Location & Local Information
Surface water temperatures at Thomas Hill Reservoir vary with the seasons and weather. In winter the lake commonly drops into the low 30s to low 40s °F (about 1–6 °C), while spring warming typically brings surface readings into the mid‑40s to mid‑60s °F (roughly 7–18 °C). Peak summer conditions often produce the warmest surface temperatures, frequently reaching the low 70s up to the mid‑80s °F (approximately 22–30 °C) on hot afternoons. In autumn the reservoir cools back into the 50s and lower 70s °F (about 10–21 °C). Like many impoundments, Thomas Hill can develop surface warming and a thermocline in summer, so deeper water remains notably colder than the surface.
Swimming is possible when local rules and posted signs permit, but access and use are shaped by safety and operational considerations. Designated shoreline areas are safest during the warmer months—generally late spring through early fall—because water temperatures are more comfortable and the risk of cold‑water shock is lower. Restrictions may be in place around boat ramps, intake structures, or areas managed for other uses, and swimmers should be mindful of sudden temperature changes, submerged hazards, and local regulations before entering the water.