Otter Lake — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Otter Lake, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Otter Lake today is 18.4°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 | 21.0°C | 20.0°C | |
| OCT 6 | 20.7°C | 20.0°C | |
| OCT 7 | 20.1°C | 20.0°C | |
| OCT 8 | 19.4°C | 20.0°C | |
| OCT 9 | 19.7°C | 20.0°C | |
| OCT 10 | 19.7°C | 20.0°C | |
| OCT 11 | 18.9°C | 20.0°C | |
| OCT 12 | 19.1°C | 20.0°C | |
| OCT 13 | 20.0°C | 18.5°C | |
| OCT 14 | 20.0°C | 18.6°C | |
| OCT 15 | 20.0°C | 18.6°C | |
| OCT 16 | 20.0°C | 18.7°C | |
| OCT 17 | 20.0°C | 18.8°C | |
| OCT 18 | 20.0°C | 18.9°C | |
| OCT 19 | 20.0°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 | 1°C | 3°C | 6°C |
| February | 1°C | 3°C | 6°C |
| March | 2°C | 7°C | 11°C |
| April | 6°C | 12°C | 19°C |
| May | 16°C | 20°C | 24°C |
| June | 20°C | 23°C | 26°C |
| July | 24°C | 28°C | 31°C |
| August | 23°C | 26°C | 29°C |
| September | 22°C | 25°C | 27°C |
| October | 16°C | 20°C | 24°C |
| November | 7°C | 12°C | 16°C |
| December | 2°C | 6°C | 8°C |
Otter Lake: Water Temperature by Location
Otter Lake: Weather Forecast
October 13
October 14
October 15
October 16
October 17
October 18
Location & Local Information
Otter Lake in Illinois typically follows the seasonal pattern of many small Midwestern lakes, with surface temperatures changing markedly through the year. In spring the water is cool, often around 40–65°F (4–18°C) as snowmelt and runoff keep temperatures low. By summer the surface commonly warms to roughly 70–85°F (21–29°C), especially in shallower areas and on sunny days, while deeper pockets stay cooler. In fall temperatures decline again to about 50–70°F (10–21°C) as air cools and the lake begins to mix. In winter the surface may approach freezing, roughly 32–40°F (0–4°C), and portions can ice over depending on local conditions. Actual readings vary day to day, with depth, wind, and recent weather driving short‑term changes.
Swimming is generally possible during the warmer months when surface temperatures are comfortable, but whether it is allowed depends on local rules, property access and current water quality. Warm summer temperatures make recreational swimming attractive, yet closures or advisories can be issued for high bacteria counts, harmful algal blooms, submerged hazards, or private‑property restrictions. There are often no lifeguards at smaller lakes, and colder water below the surface can increase risk of cold shock, so swimmers should heed posted signs, check with local authorities about advisories, and take normal safety precautions.