Fontenelle Reservoir — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Fontenelle Reservoir, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Fontenelle Reservoir today is 7.1°C.
Water Temperature: Daily Trends, Historical Records, and Forecast
❌ As of today, the minimum water temperature ranges from 41°F (5°C) to 47°F (8°C). This water temperature is still quite low, and swimming in such conditions may only be comfortable for hardened individuals. It is recommended to limit the time spent in the water to avoid hypothermia. For those not accustomed to cold water, it is better to refrain from swimming. However, if you decide to enter the water, it is advisable to wear a warm wetsuit for protection against the cold. 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 |
|---|---|---|---|
| APR 11 | 5.8°C | 6.0°C | |
| APR 12 | 6.3°C | 6.0°C | |
| APR 13 | 7.1°C | 6.0°C | |
| APR 14 | 7.1°C | 6.0°C | |
| APR 15 | 6.7°C | 6.0°C | |
| APR 16 | 6.6°C | 6.0°C | |
| APR 17 | 7.8°C | 6.0°C | |
| APR 18 | 7.6°C | 6.0°C | |
| APR 19 | 6.0°C | 7.0°C | |
| APR 20 | 6.0°C | 7.0°C | |
| APR 21 | 6.0°C | 6.9°C | |
| APR 22 | 6.0°C | 6.9°C | |
| APR 23 | 6.0°C | 6.8°C | |
| APR 24 | 6.0°C | 6.8°C | |
| APR 25 | 6.0°C | 6.7°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 | 2°C | 4°C |
| February | 1°C | 5°C | 8°C |
| March | 2°C | 6°C | 10°C |
| April | 3°C | 6°C | 9°C |
| May | 4°C | 10°C | 15°C |
| June | 12°C | 17°C | 22°C |
| July | 18°C | 24°C | 30°C |
| August | 18°C | 21°C | 23°C |
| September | 16°C | 20°C | 24°C |
| October | 7°C | 12°C | 16°C |
| November | 3°C | 6°C | 9°C |
| December | 0°C | 2°C | 5°C |
Fontenelle Reservoir: Water Temperature by Location
Fontenelle Reservoir: Weather Forecast
April 19
April 20
April 21
April 22
April 23
April 24
Location & Local Information
Fontenelle Reservoir on the Green River typically stays cool through much of the year because of its size and mountain-fed sources. Surface temperatures in winter commonly hover near freezing, roughly 32°F (0°C) and can remain just above that when ice does not form. In spring and fall the surface usually ranges from about 35–55°F (2–13°C) as runoff and cooler air keep the water chilly. During the warmest summer weeks the reservoir can warm into the mid-60s to low 70s °F, about 18–22°C at the surface in sheltered, shallow bays; however, deeper and open-water areas remain noticeably colder even in July and August.
Swimming is generally permitted at Fontenelle because the reservoir is a public recreation area, and people commonly boat, fish, and wade along its shores. That said, caution is advised: cold temperatures, sudden drop-offs, boat traffic, and the absence of lifeguards or regular safety patrols make open-water swimming risky. Hypothermia can set in quickly when water is below about 60°F (15.5°C), so even summer swims may be brief. Visitors should follow posted rules, choose sheltered shallow areas, wear a life jacket if swimming near boats, and check local advisories for seasonal restrictions or safety updates before entering the water.