Lake Hattie Reservoir — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Lake Hattie Reservoir, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Lake Hattie Reservoir today is 19.4°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 |
|---|---|---|---|
| JUN 23 | 19.1°C | 17.0°C | |
| JUN 24 | 18.2°C | 17.0°C | |
| JUN 25 | 18.2°C | 17.0°C | |
| JUN 26 | 18.5°C | 17.0°C | |
| JUN 27 | 19.0°C | 17.0°C | |
| JUN 28 | 19.8°C | 17.0°C | |
| JUN 29 | 19.8°C | 17.0°C | |
| JUN 30 | 19.8°C | 17.0°C | |
| JUL 1 | 23.0°C | 19.6°C | |
| JUL 2 | 23.0°C | 19.8°C | |
| JUL 3 | 23.0°C | 19.9°C | |
| JUL 4 | 23.0°C | 20.1°C | |
| JUL 5 | 23.0°C | 20.3°C | |
| JUL 6 | 23.0°C | 20.5°C | |
| JUL 7 | 23.0°C | 20.7°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 | 5°C |
| February | 0°C | 2°C | 5°C |
| March | 0°C | 5°C | 10°C |
| April | 4°C | 7°C | 11°C |
| May | 7°C | 11°C | 16°C |
| June | 13°C | 17°C | 21°C |
| July | 20°C | 23°C | 26°C |
| August | 20°C | 23°C | 26°C |
| September | 17°C | 21°C | 24°C |
| October | 8°C | 14°C | 19°C |
| November | 3°C | 9°C | 14°C |
| December | 2°C | 5°C | 7°C |
Lake Hattie Reservoir: Water Temperature by Location
Lake Hattie Reservoir: Weather Forecast
July 1
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July 4
Location & Local Information
Lake Hattie Reservoir is a mountain impoundment in Wyoming, so its water temperatures reflect elevation, seasonal snowmelt and depth. In spring, as snowmelt and cool runoff dominate, surface temperatures commonly sit around 35–50°F (2–10°C). By early summer temperatures often rise to roughly 50–60°F (10–15°C), with the warmest weeks of July and August sometimes bringing surface water into the mid-60s to low 70s °F (about 18–22°C) in shallow, sun-exposed areas. Autumn sees a steady decline back toward 40–55°F (4–13°C) as air temperatures cool, and in winter the reservoir is cold enough to form ice with near-freezing water beneath—typically around 32–39°F (0–4°C) under ice cover. Actual temperatures vary with year-to-year weather, wind and the specific depth or bay of the reservoir.
Swimming is generally possible at Lake Hattie during the warmer months, because it is an accessible recreational waterbody and not universally closed to contact activities. That said, there are no lifeguards or warming facilities, and the water remains cold compared with lowland lakes, producing hypothermia risk even on warm days. Other factors—such as sudden drop-offs, submerged hazards, seasonal changes in outflow or local regulations—can further limit safe swimming, so visitors should obey posted rules and use caution if entering the water.