Cottage Grove Lake — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Cottage Grove Lake, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Cottage Grove Lake today is 23.1°C.
Water Temperature: Daily Trends, Historical Records, and Forecast
✅ As of today, the minimum water temperature ranges from 75°F (23°C) to 79°F (26°C). This is a very comfortable temperature for swimming, and many people can enjoy prolonged stays in the water without feeling cold. The water is pleasantly warm, making it ideal for relaxation and water sports. This temperature range is particularly popular among tourists, as it combines comfort and safety for health. 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 |
|---|---|---|---|
| AUG 4 | 22.2°C | 22.0°C | |
| AUG 5 | 22.5°C | 22.0°C | |
| AUG 6 | 22.8°C | 22.0°C | |
| AUG 7 | 22.9°C | 22.0°C | |
| AUG 8 | 23.1°C | 22.0°C | |
| AUG 9 | 23.3°C | 22.0°C | |
| AUG 10 | 23.4°C | 22.0°C | |
| AUG 11 | 23.3°C | 22.0°C | |
| AUG 12 | 22.0°C | 23.0°C | |
| AUG 13 | 22.0°C | 23.0°C | |
| AUG 14 | 22.0°C | 22.9°C | |
| AUG 15 | 22.0°C | 22.9°C | |
| AUG 16 | 22.0°C | 22.8°C | |
| AUG 17 | 22.0°C | 22.8°C | |
| AUG 18 | 22.0°C | 22.7°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 | 7°C |
| February | 0°C | 4°C | 8°C |
| March | 1°C | 6°C | 10°C |
| April | 9°C | 12°C | 15°C |
| May | 12°C | 17°C | 21°C |
| June | 13°C | 19°C | 23°C |
| July | 16°C | 21°C | 26°C |
| August | 17°C | 22°C | 27°C |
| September | 18°C | 20°C | 22°C |
| October | 10°C | 14°C | 18°C |
| November | 4°C | 8°C | 13°C |
| December | 4°C | 7°C | 11°C |
Cottage Grove Lake: Water Temperature by Location
Cottage Grove Lake: Weather Forecast
August 12
August 13
August 14
August 15
Location & Local Information
Cottage Grove Lake is a managed reservoir in Oregon’s Willamette Valley whose surface temperatures change markedly with the seasons. In spring (March–May) surface water typically ranges from roughly 45–60°F (7–16°C) as runoff cools the basin. Summer (June–August) brings the warmest conditions, with surface temperatures commonly between about 60–75°F (16–24°C) on sunny days, though deeper water remains cooler. In fall (September–November) temperatures generally decline to roughly 50–65°F (10–18°C), and winter (December–February) surface readings often sit in the 40–50°F range (4–10°C). These values are approximate; actual temperatures vary by weather, depth, and time of day.
Swimming at Cottage Grove Lake is permitted in day‑use and beach areas because the reservoir is managed for multiple recreational uses, including swimming, boating and fishing. However, there are typically no lifeguards, and local rules and posted advisories should be followed. Water quality conditions such as elevated bacteria or harmful algal blooms can occur seasonally, and cold water temperatures—even in summer below the surface—present a risk of cold‑water shock or hypothermia. Visitors are advised to check current park notices, swim in designated zones, wear flotation for open‑water swimming, and avoid entering the water during posted advisories.