Lake Jonku — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Lake Jonku, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Lake Jonku today is 10.8°C.
Water Temperature: Daily Trends, Historical Records, and Forecast
❌ As of today, the minimum water temperature ranges from 50°F (10°C) to 54°F (12°C). The water is slightly warmer, but still cool for most people. Swimming in such conditions is possible, but for most people, the time spent in the water should be limited to avoid hypothermia. Even experienced swimmers may feel discomfort if they stay in the water for too long. To improve comfort and safety, a wetsuit can be used. 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 |
|---|---|---|---|
| SEP 14 | 12.5°C | 12.0°C | |
| SEP 15 | 12.3°C | 12.0°C | |
| SEP 16 | 12.3°C | 12.0°C | |
| SEP 17 | 11.7°C | 12.0°C | |
| SEP 18 | 11.1°C | 12.0°C | |
| SEP 19 | 11.3°C | 12.0°C | |
| SEP 20 | 11.0°C | 12.0°C | |
| SEP 21 | 10.8°C | 12.0°C | |
| SEP 22 | 12.0°C | 10.9°C | |
| SEP 23 | 12.0°C | 10.9°C | |
| SEP 24 | 12.0°C | 11.0°C | |
| SEP 25 | 12.0°C | 11.0°C | |
| SEP 26 | 12.0°C | 11.1°C | |
| SEP 27 | 12.0°C | 11.2°C | |
| SEP 28 | 12.0°C | 11.2°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 | 2°C | 4°C |
| February | 0°C | 2°C | 4°C |
| March | 0°C | 2°C | 4°C |
| April | 0°C | 2°C | 4°C |
| May | 3°C | 8°C | 13°C |
| June | 9°C | 14°C | 20°C |
| July | 14°C | 20°C | 25°C |
| August | 12°C | 18°C | 23°C |
| September | 7°C | 12°C | 18°C |
| October | 1°C | 5°C | 8°C |
| November | 0°C | 2°C | 4°C |
| December | 0°C | 2°C | 4°C |
Lake Jonku: Water Temperature by Location
Lake Jonku: Weather Forecast
September 21
September 22
September 23
September 24
September 25
September 26
Location & Local Information
Lake Jonku, known in Finnish as Jongunjärvi, is located in North Ostrobothnia near the municipality of Suomussalmi. It is a clear, calm lake surrounded by forests and marshland, forming part of the Oulujoki river basin. The water remains cool for most of the year due to the lake’s northern location and relatively high altitude. In spring, after the ice melts in May, the surface temperature is around 4–7 °C (39–45 °F). During early summer, it gradually rises to 13–16 °C (55–61 °F), and in July, the warmest period, Jongunjärvi typically reaches 17–20 °C (63–68 °F). On hot days, shallow shores can briefly warm to 21–22 °C (70–72 °F). By late September, the water cools again below 10 °C (50 °F), and the lake usually freezes in November.
Swimming in Lake Jonku is allowed and pleasant during the short northern summer. The water is pure and suitable for bathing, though it remains fresh and cool even in midsummer. Locals and visitors swim from small sandy beaches or wooden piers, enjoying the lake’s peaceful surroundings and unspoiled nature. While long swims may feel chilly, the clean, clear water provides a refreshing and authentic experience of Finland’s northern wilderness.