Lake Lillinonah — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Lake Lillinonah, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Lake Lillinonah today is 19.9°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 |
|---|---|---|---|
| SEP 14 | 21.6°C | 23.0°C | |
| SEP 15 | 21.7°C | 23.0°C | |
| SEP 16 | 20.4°C | 23.0°C | |
| SEP 17 | 20.7°C | 23.0°C | |
| SEP 18 | 20.9°C | 23.0°C | |
| SEP 19 | 21.0°C | 23.0°C | |
| SEP 20 | 21.1°C | 23.0°C | |
| SEP 21 | 19.9°C | 23.0°C | |
| SEP 22 | 23.0°C | 20.1°C | |
| SEP 23 | 23.0°C | 20.2°C | |
| SEP 24 | 23.0°C | 20.4°C | |
| SEP 25 | 23.0°C | 20.5°C | |
| SEP 26 | 23.0°C | 20.7°C | |
| SEP 27 | 23.0°C | 20.8°C | |
| SEP 28 | 23.0°C | 21.0°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 | 3°C | 5°C |
| February | 1°C | 3°C | 6°C |
| March | 1°C | 4°C | 8°C |
| April | 5°C | 10°C | 15°C |
| May | 12°C | 17°C | 21°C |
| June | 16°C | 20°C | 24°C |
| July | 22°C | 27°C | 31°C |
| August | 22°C | 26°C | 29°C |
| September | 20°C | 23°C | 26°C |
| October | 13°C | 17°C | 21°C |
| November | 6°C | 10°C | 13°C |
| December | 2°C | 6°C | 8°C |
Lake Lillinonah: Water Temperature by Location
Lake Lillinonah: Weather Forecast
September 21
September 22
September 23
September 24
September 25
September 26
Location & Local Information
Lake Lillinonah’s water follows the seasonal pattern typical of Connecticut reservoirs. In spring (March–May) surface temperatures commonly rise from about 40–60°F (4–15°C) as runoff and air temperatures increase. By summer (June–August) the top layer of the lake often warms to roughly 70–80°F (21–27°C), with late-summer highs occasionally a few degrees warmer on calm, sunny days. Autumn (September–November) brings cooling water in the range of roughly 50–65°F (10–18°C) as nights lengthen, and in winter (December–February) temperatures drop toward freezing, roughly 32–40°F (0–4°C), with ice forming in sheltered coves in colder winters.
Swimming on Lake Lillinonah is possible in the sense that people do swim there, but organized public swimming opportunities are limited. The shoreline is largely private and there are few formal lifeguarded beaches, so municipalities and landowners often restrict or discourage casual swimming because of hazards such as boat traffic, variable currents near the dam and inlets, sudden depth changes, submerged objects, and occasional water-quality advisories. For those considering a swim, the safest approach is to use designated public waterfronts where provided, follow local rules, watch for boating activity, and be mindful of cold-water risks and lack of lifeguards.