Rock Lake — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Rock Lake, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Rock Lake today is 19.1°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 13 | 19.7°C | 21.2°C | |
| SEP 14 | 19.8°C | 21.2°C | |
| SEP 15 | 20.0°C | 21.2°C | |
| SEP 16 | 19.6°C | 21.2°C | |
| SEP 17 | 19.8°C | 21.2°C | |
| SEP 18 | 19.4°C | 21.2°C | |
| SEP 19 | 19.4°C | 21.2°C | |
| SEP 20 | 19.0°C | 21.2°C | |
| SEP 21 | 21.2°C | 19.2°C | |
| SEP 22 | 21.2°C | 19.3°C | |
| SEP 23 | 21.2°C | 19.4°C | |
| SEP 24 | 21.2°C | 19.5°C | |
| SEP 25 | 21.2°C | 19.6°C | |
| SEP 26 | 21.2°C | 19.7°C | |
| SEP 27 | 21.2°C | 19.8°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 | 2°C | 4°C |
| February | 1°C | 4°C | 6°C |
| March | 1°C | 5°C | 8°C |
| April | 5°C | 9°C | 14°C |
| May | 9°C | 15°C | 21°C |
| June | 16°C | 20°C | 24°C |
| July | 20°C | 26°C | 31°C |
| August | 21°C | 24°C | 26°C |
| September | 18°C | 21°C | 25°C |
| October | 6°C | 13°C | 20°C |
| November | 2°C | 9°C | 15°C |
| December | 0°C | 2°C | 5°C |
Rock Lake: Water Temperature by Location
Rock Lake: Weather Forecast
September 21
September 22
September 23
September 24
September 25
September 26
Location & Local Information
Rock Lake in Wisconsin experiences typical midwestern seasonal water temperatures. In spring the lake usually warms from near-freezing after ice-out to roughly 40–60°F (4–16°C) as air temperatures rise. Summer surface temperatures commonly range from about 68–78°F (20–26°C), and on hot, shallow bays surface readings can reach the low 80s °F (around 27–28°C). By early fall the water cools back into the 50–65°F range (10–18°C) before freezing again; during winter the surface under ice hovers near 32°F (0°C) while deeper layers remain closer to freshwater’s maximum density temperature around 39°F (4°C).
Swimming is generally allowed at Rock Lake during the open-water season, particularly at public access points and informal beach areas, because the lake supports recreational use. Comfort and safety depend on water temperature, weather, and water quality; many swimmers prefer temperatures above about 70°F (21°C), while cooler water can cause rapid heat loss. Local health or parks departments may temporarily restrict swimming when bacterial levels or harmful algal blooms are detected, and ice cover in winter makes open-water swimming unsafe except under supervised, prepared conditions. Always check current advisories and use standard water-safety precautions.