Fresno Reservoir — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Fresno Reservoir, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Fresno Reservoir today is 13.1°C.
Water Temperature: Daily Trends, Historical Records, and Forecast
⚠️ As of today, the minimum water temperature ranges from 54°F (12°C) to 60°F (15°C). The water is significantly warmer, and swimming becomes possible for most people. However, caution may still be required for prolonged stays in the water, as extended exposure can cause discomfort. This is a suitable temperature range for short swims and for those accustomed to cooler water. For more comfortable swimming, it is recommended to use proper gear. 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 | 13.9°C | 11.0°C | |
| OCT 6 | 13.4°C | 11.0°C | |
| OCT 7 | 13.6°C | 11.0°C | |
| OCT 8 | 13.2°C | 11.0°C | |
| OCT 9 | 13.3°C | 11.0°C | |
| OCT 10 | 12.2°C | 11.0°C | |
| OCT 11 | 13.0°C | 11.0°C | |
| OCT 12 | 13.7°C | 11.0°C | |
| OCT 13 | 11.0°C | 13.0°C | |
| OCT 14 | 11.0°C | 12.9°C | |
| OCT 15 | 11.0°C | 12.8°C | |
| OCT 16 | 11.0°C | 12.7°C | |
| OCT 17 | 11.0°C | 12.6°C | |
| OCT 18 | 11.0°C | 12.5°C | |
| OCT 19 | 11.0°C | 12.4°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 | 6°C | 12°C |
| May | 4°C | 12°C | 20°C |
| June | 9°C | 17°C | 24°C |
| July | 16°C | 21°C | 27°C |
| August | 17°C | 22°C | 27°C |
| September | 13°C | 18°C | 23°C |
| October | 4°C | 11°C | 18°C |
| November | 3°C | 7°C | 10°C |
| December | 2°C | 7°C | 10°C |
Fresno Reservoir: Water Temperature by Location
Fresno Reservoir: Weather Forecast
October 13
October 14
October 15
October 16
October 17
Location & Local Information
Fresno Reservoir in Montana typically experiences a strong seasonal cycle in surface water temperature. In spring the lake usually remains quite cold, often ranging from about 40–55°F (4–13°C) as snowmelt and cool air keep temperatures down. Peak summer warming can push surface temperatures into the mid‑60s to mid‑70s, roughly 60–75°F (16–24°C), especially during calm, sunny stretches. Autumn brings cooling back to roughly 45–60°F (7–16°C) before ice forms, and winter conditions drive surface water toward freezing; areas of the reservoir may be at or near 32°F (0°C) and develop ice cover depending on winter severity. Deep water remains colder year‑round than the surface.
Swimming at Fresno Reservoir is generally allowed on a seasonal basis where public access is provided, but it is governed by local management, water quality, and safety considerations. The primary reasons for permitting or restricting swimming include the cold temperatures that increase hypothermia risk even on warm days, variable water quality after runoff events, absence of lifeguards, boat traffic and submerged hazards, and periods of ice cover in winter. Visitors should check on-site signage and local rules, be aware of sudden temperature changes, and take precautions such as wearing a wetsuit or staying close to shore when entering these waters.