France · Loire-Atlantique
Sea temperature at La Source
Pleasant for swimming
Updated hourly from the live marine forecast. See the 12-month typical range and, where available, real measured readings further down the page.
7-day outlook
7-day sea temperature forecast from Open-Meteo, refreshed hourly.
Sea temperature
Next 7 days, °C
View as table
| Day | Sea temp (°C) |
|---|---|
| Wed 2 | 21.7 |
| Thu 3 | 21.8 |
| Fri 4 | 22.0 |
| Sat 5 | 22.8 |
| Sun 6 | 22.5 |
| Mon 7 | 22.6 |
| Tue 8 | 22.4 |
Sea temperature by month
Modeled climatology derived from latitude and season.
Typical vs. measured sea temperature
12-month view, °C — modeled line vs. measured sample averages
View as table
| Month | Modeled (°C) | Measured avg. (°C) |
|---|---|---|
| Jan | 15 | — |
| Feb | 14 | — |
| Mar | 15 | — |
| Apr | 17 | — |
| May | 19 | — |
| Jun | 22 | — |
| Jul | 23 | — |
| Aug | 24 | — |
| Sep | 24 | — |
| Oct | 22 | — |
| Nov | 20 | — |
| Dec | 17 | — |
No measured in-season sea temperature has been published for La Source yet — the chart above shows the modeled climatology only. Some countries (Croatia, via IZOR) also record the sea temperature at each official water sample; check the water quality page for this beach's sampling status.
Frequently asked questions
How cold or warm is the water at La Source today?
La Source's sea temperature is currently around 21°C, based on the most recent hourly reading. See the 7-day chart above for the short-term trend and the monthly chart further down for the seasonal typical. That's the reading right off Loire-Atlantique.
What's the best month to visit La Source for swimming?
Aim for July–September — the modeled water temperature typically clears 22°C in that window, the rule of thumb for comfortably warm swimming, with August usually the peak. That applies to the water around Loire-Atlantique.
Is the sea temperature chart above measured or estimated?
Not currently for La Source — the chart above is a modeled estimate based on latitude and season rather than a measured average. A few countries (Croatia, via IZOR) do publish the sea temperature taken at each official water sample, and that's plotted alongside the modeled curve when it exists.