Ennis Lake — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Ennis Lake, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Ennis Lake today is 3.3°C.
Water Temperature: Daily Trends, Historical Records, and Forecast
❌ As of today, the minimum water temperature ranges less than 41°F (5°C). Such water is extremely cold and not recommended for swimming without proper preparation. In these conditions, the risk of hypothermia is very high, and prolonged exposure to the water can be hazardous to your health. If you decide to swim, it is important to have the appropriate gear, such as a wetsuit. Typically, only experienced swimmers or those who practice winter swimming venture into such waters. 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 26 | 5.9°C | 9.5°C | |
| OCT 27 | 7.1°C | 9.5°C | |
| OCT 28 | 6.6°C | 9.5°C | |
| OCT 29 | 5.4°C | 9.5°C | |
| OCT 30 | 4.9°C | 9.5°C | |
| OCT 31 | 6.3°C | 9.5°C | |
| NOV 1 | 5.5°C | 5.5°C | |
| NOV 2 | 3.3°C | 5.5°C | |
| NOV 3 | 5.5°C | 3.4°C | |
| NOV 4 | 5.5°C | 3.5°C | |
| NOV 5 | 5.5°C | 3.6°C | |
| NOV 6 | 5.5°C | 3.7°C | |
| NOV 7 | 5.5°C | 3.9°C | |
| NOV 8 | 5.5°C | 4.0°C | |
| NOV 9 | 5.5°C | 4.1°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 | 4°C | 6°C |
| February | 1°C | 4°C | 7°C |
| March | 1°C | 5°C | 9°C |
| April | 0°C | 5°C | 10°C |
| May | 4°C | 10°C | 17°C |
| June | 9°C | 13°C | 18°C |
| July | 14°C | 19°C | 25°C |
| August | 17°C | 20°C | 24°C |
| September | 13°C | 16°C | 20°C |
| October | 4°C | 10°C | 15°C |
| November | 0°C | 6°C | 10°C |
| December | 2°C | 5°C | 7°C |
Ennis Lake: Water Temperature by Location
Ennis Lake: Weather Forecast
November 3
November 4
November 5
November 6
Location & Local Information
Ennis Lake, a reservoir on the Madison River in southwestern Montana, stays relatively cool through much of the year because of its elevation and river-fed source. Typical seasonal surface temperatures are roughly 35–50°F (2–10°C) in spring as snowmelt and runoff dominate, warming to about 50–60°F (10–16°C) in early summer. The warmest period is usually mid- to late summer, when surface readings commonly reach 60–70°F (15–21°C) and on hot spells may approach 70–75°F (21–24°C). By fall the water cools again to roughly 40–55°F (4–13°C), and in winter the lake can approach freezing, about 32–36°F (0–2°C), with ice possible depending on conditions.
Swimming is generally allowed in Ennis Lake because it is a public reservoir, but opportunities are limited by the consistently cool temperatures, a short comfortable season, and safety considerations. Even in summer, colder depths and swift inflows can produce hypothermia risk, and there is boat traffic and occasional currents near the dam and inlets. As a result, most recreational swimming occurs only during the warmest weeks, and swimmers are advised to be cautious and mindful of changing conditions rather than assuming prolonged warm-water swimming is available.