Semily — Current Water Temperature, Annual Trends and Forecast
This page provides information on the current water temperature in Semily, trends, monthly ranges and the forecast for the coming days.
Current Water Temperature
Water Temperature in Semily today is 18.9°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 |
|---|---|---|---|
| AUG 4 | 19.1°C | 18.0°C | |
| AUG 5 | 21.0°C | 18.0°C | |
| AUG 6 | 20.1°C | 18.0°C | |
| AUG 7 | 20.4°C | 18.0°C | |
| AUG 8 | 20.2°C | 18.0°C | |
| AUG 9 | 19.7°C | 18.0°C | |
| AUG 10 | 19.1°C | 18.0°C | |
| AUG 12 | 18.0°C | 18.9°C | |
| AUG 13 | 18.0°C | 18.8°C | |
| AUG 14 | 18.0°C | 18.8°C | |
| AUG 15 | 18.0°C | 18.7°C | |
| AUG 16 | 18.0°C | 18.7°C | |
| AUG 17 | 18.0°C | 18.6°C | |
| AUG 18 | 18.0°C | 18.6°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 | 5°C | 9°C |
| February | 1°C | 5°C | 9°C |
| March | 3°C | 7°C | 11°C |
| April | 4°C | 10°C | 16°C |
| May | 7°C | 14°C | 21°C |
| June | 11°C | 17°C | 22°C |
| July | 14°C | 19°C | 24°C |
| August | 13°C | 18°C | 23°C |
| September | 10°C | 15°C | 19°C |
| October | 7°C | 12°C | 16°C |
| November | 2°C | 9°C | 16°C |
| December | 1°C | 5°C | 8°C |
Semily: Weather Forecast
August 11
August 12
August 13
August 14
Location & Local Information
In Semily, the Jizera River flows through a picturesque setting surrounded by rolling hills and forested areas. Because the river is fed by mountain streams, its water remains relatively cool throughout the year. In late spring, temperatures usually range around 14–16 °C, while in July and August they can rise to 17–19 °C on warmer days. This makes swimming refreshing, though the cooler temperature is better suited for short dips rather than long, leisurely swims.
Swimming directly in the Jizera within Semily is limited, as the urban riverbanks are not specifically developed for bathing. However, there are some calmer and shallower sections where locals occasionally enjoy a brief dip. The gentle current in these areas allows for safe wading or short swims, though caution is always advised due to the river’s natural flow.
For more comfortable bathing, residents often visit nearby ponds or small recreational lakes where the water warms more quickly and facilities are available. Nevertheless, the Jizera in Semily provides a natural, scenic option for those who enjoy cooler river water and a refreshing escape on hot summer days.