Swift Reservoir — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Swift Reservoir, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Swift Reservoir today is 21°C.
Water Temperature: Daily Trends, Historical Records, and Forecast
✅ As of today, the minimum water temperature ranges from 68°F (20°C) to 74°F (23°C). The water is warm and pleasant for swimming, and in this range, one can stay in the water for extended periods without the risk of hypothermia. This is the ideal temperature for relaxation, swimming, and water sports. Families with children, as well as outdoor enthusiasts, will enjoy swimming and time spent in the water. For most people, this is the optimal temperature for a comfortable beach experience. 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 24 | 20.9°C | 25.0°C | |
| AUG 25 | 21.1°C | 25.0°C | |
| AUG 26 | 21.1°C | 25.0°C | |
| AUG 27 | 21.1°C | 25.0°C | |
| AUG 28 | 21.1°C | 25.0°C | |
| AUG 29 | 21.3°C | 25.0°C | |
| AUG 30 | 21.3°C | 25.0°C | |
| AUG 31 | 21.0°C | 25.0°C | |
| SEP 1 | 21.5°C | 21.0°C | |
| SEP 2 | 21.5°C | 21.1°C | |
| SEP 3 | 21.5°C | 21.1°C | |
| SEP 4 | 21.5°C | 21.1°C | |
| SEP 5 | 21.5°C | 21.1°C | |
| SEP 6 | 21.5°C | 21.2°C | |
| SEP 7 | 21.5°C | 21.2°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 | 6°C |
| February | 2°C | 5°C | 8°C |
| March | 3°C | 7°C | 11°C |
| April | 5°C | 10°C | 15°C |
| May | 10°C | 16°C | 21°C |
| June | 13°C | 19°C | 24°C |
| July | 16°C | 24°C | 31°C |
| August | 20°C | 25°C | 30°C |
| September | 17°C | 22°C | 26°C |
| October | 12°C | 16°C | 20°C |
| November | 6°C | 10°C | 14°C |
| December | 4°C | 7°C | 9°C |
Swift Reservoir: Water Temperature by Location
Swift Reservoir: Weather Forecast
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September 4
September 5
Location & Local Information
Swift Reservoir’s surface water temperatures vary widely through the year, reflecting the cool mountain climate of Washington. In winter the surface often sits near freezing, roughly 33–40°F (1–4°C). Spring warming brings temperatures into the 40–55°F range (4–13°C) as runoff and air temperatures rise. By summer the warmest surface readings typically occur, commonly about 60–72°F (15–22°C) in calmer, sun-exposed areas, though deeper or shaded sections remain substantially colder. In fall the reservoir cools again, with surface conditions generally falling back into the 45–60°F band (7–16°C) as daylight shortens and inflow temperatures drop.
Swimming is possible at Swift Reservoir, but conditions and safety considerations strongly influence whether it is advisable at any given time. Because it is a managed water body with variable water levels, cold thermoclines, and potential currents near inlets, outlets, or dam structures, public access and safe swimming spots are often limited; signage and local regulations should be observed. Recreational swimming is most comfortable in summer when surface temperatures reach the upper ranges, while spring, fall, and especially winter present a higher risk of cold-water shock and hypothermia, so caution, proper gear, and awareness of local rules are recommended.