Numedalslågen River — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in the Numedalslågen River, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in the Numedalslågen River today is 12°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 |
|---|---|---|---|
| JUN 3 | 10.7°C | 15.4°C | |
| JUN 4 | 10.7°C | 15.4°C | |
| JUN 5 | 11.0°C | 15.4°C | |
| JUN 6 | 11.0°C | 15.4°C | |
| JUN 7 | 12.0°C | 15.4°C | |
| JUN 8 | 12.0°C | 15.4°C | |
| JUN 10 | 12.0°C | 15.4°C | |
| JUN 11 | 15.4°C | 12.2°C | |
| JUN 12 | 15.4°C | 12.3°C | |
| JUN 13 | 15.4°C | 12.5°C | |
| JUN 14 | 15.4°C | 12.7°C | |
| JUN 15 | 15.4°C | 12.9°C | |
| JUN 16 | 15.4°C | 13.0°C | |
| JUN 17 | 15.4°C | 13.2°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 | 5°C |
| February | 0°C | 2°C | 5°C |
| March | 0°C | 3°C | 6°C |
| April | 2°C | 6°C | 9°C |
| May | 6°C | 10°C | 15°C |
| June | 10°C | 15°C | 20°C |
| July | 14°C | 18°C | 23°C |
| August | 14°C | 18°C | 23°C |
| September | 10°C | 15°C | 19°C |
| October | 6°C | 9°C | 12°C |
| November | 2°C | 6°C | 9°C |
| December | 0°C | 3°C | 6°C |
Numedalslågen River: Water Temperature by Location
Numedalslågen River: Weather Forecast
June 9
June 10
June 11
June 12
June 13
Location & Local Information
Source Hardangervidda plateau
• location Eidfjord, Vestland
• coordinates 60.234570°N 7.29217529°E
• elevation 1,405 metres (4,610 ft)
Mouth Larviksfjorden
• location Larvik, Vestfold
• coordinates 59.0376403°N 10.055065°E
• elevation 0 metres (0 ft)
Length 356 km (221 mi)
Numedalslågen (Norwegian: Numedalslågen) is a major river in southern Norway whose water temperature varies widely with season, altitude and local flow. In winter the river is very cold, typically around 0–4 °C (32–39 °F) in many stretches, while spring snowmelt can keep temperatures low, roughly 1–10 °C (34–50 °F) depending on runoff. In summer the warmer lowland sections can reach about 8–18 °C (46–64 °F) on average, though shaded, fast-flowing or higher-altitude stretches tend to remain colder. Autumn cooling usually brings temperatures down to roughly 4–12 °C (39–54 °F) as air temperatures drop and flows increase.
Swimming in Numedalslågen is possible in many accessible, calmer stretches and during the warmest months, but it is governed by practical safety considerations rather than blanket prohibitions. Cold water, strong currents, submerged obstacles and sudden flow changes from hydropower releases make some parts hazardous even in summer. Local advisories, posted signs and anglers’ or landowners’ guidance should be checked before entering the water. For safer swimming choose slow, shallow banks, use appropriate thermal protection such as a wetsuit in cooler conditions, and avoid areas near rapids, dams or boat traffic.