Petite Lake — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Petite Lake, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Petite Lake today is 19°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 | 20.8°C | 19.0°C | |
| SEP 15 | 21.5°C | 19.0°C | |
| SEP 16 | 18.5°C | 19.0°C | |
| SEP 17 | 18.7°C | 19.0°C | |
| SEP 18 | 19.1°C | 19.0°C | |
| SEP 19 | 19.5°C | 19.0°C | |
| SEP 20 | 19.0°C | 19.0°C | |
| SEP 22 | 19.0°C | 19.0°C | |
| SEP 23 | 19.0°C | 19.0°C | |
| SEP 24 | 19.0°C | 19.0°C | |
| SEP 25 | 19.0°C | 19.0°C | |
| SEP 26 | 19.0°C | 19.0°C | |
| SEP 27 | 19.0°C | 19.0°C | |
| SEP 28 | 19.0°C | 19.0°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 | 6°C |
| February | 3°C | 6°C | 9°C |
| March | 0°C | 3°C | 7°C |
| April | 5°C | 8°C | 12°C |
| May | 9°C | 15°C | 21°C |
| June | 16°C | 19°C | 23°C |
| July | 19°C | 24°C | 30°C |
| August | 23°C | 27°C | 30°C |
| September | 13°C | 19°C | 25°C |
| October | 11°C | 15°C | 19°C |
| November | 0°C | 7°C | 14°C |
| December | 3°C | 3°C | 8°C |
Petite Lake: Water Temperature by Location
Petite Lake: Weather Forecast
September 21
September 22
September 23
September 24
September 25
September 26
Location & Local Information
Petite Lake in Illinois experiences typical Midwestern seasonal shifts in surface water temperature. In spring (March–May) surface temperatures commonly range from about 40–60°F (4–16°C) as the lake thaws and warms. Summer highs (June–August) usually bring the warmest water, often 70–80°F (21–27°C) and occasionally rising to 80–85°F (27–29°C) on hot, shallow bays. By autumn (September–November) temperatures fall to roughly 50–65°F (10–18°C) as cooling and turnover occur. In winter the surface often approaches freezing, about 32–40°F (0–4°C), and shallower areas may ice over. Because Petite Lake is relatively small and shallow in places, surface temperatures respond quickly to air temperature, and thermal stratification is typically weak or seasonal.
Swimming at Petite Lake is generally permitted during warmer months when local regulations and water-quality testing indicate it is safe, but availability depends on ownership, posted rules, and public access. Warmer summer surface temperatures make recreational swimming comfortable, but swimmers should watch for hazards such as algal blooms, sudden depth changes, boat traffic, and cold-water shock below the surface. Small, shallow bays may warm faster but are also more prone to algae. In winter swimming is discouraged due to ice and near-freezing water. Always follow signage, local health advisories, and lifeguard instructions where provided.