Lake
Longue Les Youis
Longue Les Youis water temperature is currently Warm. Conditions are welcoming. Stay hydrated and watch your sun exposure. Located in the North Temperate climate zone, it is currently summer. Recent falling temperatures have pushed the smoothed air average to 20°C. The lake has had time to absorb the warmth. Comfortable conditions for extended swimming with no wetsuit required.
Last updated:
Comfortable
Good conditions for most swimmers. Ease in and enjoy.
Recent falling temperatures have pushed the smoothed air average to 20°C. The lake has had time to absorb the warmth. Comfortable conditions for extended swimming with no wetsuit required.
Surface temperatures at their annual peak.
Lake size
Larger lakes warm and cool slowly. Ponds respond quickly to air temperature.
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What to bring
7-Day Forecast
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17.4°C
High 20.3° / Low 14°
Mild conditions, comfortable for swimming
18.3°C
54cm depth
Warm ground, water will hold temperature well
Moderate
399 W/m²
Good sunshine, noticeable surface warming
22 km/h
W, gusts 48
Moderate W wind, some surface cooling and chop
14.1°C
Feels like wet
Mild but bring a warm layer for after your swim.
26.8 mm
7-day total
27mm of rain in the last 7 days. Lake inflows may have cooled and clouded the water.
Model estimates. Always assess the water yourself before entering.
Frequently asked questions
How is the lake water temperature estimated?
Lake temperature is estimated using exponential smoothing of 60 days of air temperature data, based on Kettle et al. (2004). The algorithm accounts for lake thermal mass. Larger lakes respond more slowly to air temperature changes. This is not a direct measurement; accuracy is approximately plus or minus 2 to 3 degrees C.
What do the temperature categories mean?
Each category covers a 4 degree C band: Warm (20 degrees C or above, no wetsuit needed), Comfortable (16 to 20 degrees C, most swimmers fine), Cool (12 to 16 degrees C, wetsuit optional), Cold (8 to 12 degrees C, wetsuit recommended), Very Cold (4 to 8 degrees C, wetsuit essential), Ice Risk (below 4 degrees C, experienced swimmers only).
What is the geographic zone?
The zone is derived from the lake's latitude and altitude. It reflects the climate regime: temperate zones have the highest model accuracy; alpine and equatorial highland zones have reduced accuracy due to solar heating effects not fully captured by air temperature data alone.
What is the swimmer exit temperature?
The exit temperature uses the Steadman (1984) apparent temperature formula, which accounts for wind speed and humidity on wet skin. Exiting water in wind with wet skin causes significantly faster heat loss than the air temperature alone suggests, especially at speeds above 20 km/h.