What is the sea temperature month by month? For the destinations where we publish an official average, the water is above 21 °C (70 °F) from June to October in Malta and Crete, from July to September in Corsica (Ajaccio) and from July to October in Madeira, where it never drops below 17 °C (63 °F). In the French West Indies it stays around 25 to 27 °C (77 to 81 °F) in late winter and spring.
This page does not give today’s temperature: it brings together the monthly average water temperatures already published on our climate pages, all taken from the climate tables of the Deutscher Wetterdienst (the German meteorological service). From them we draw a ranking and a simple indicator: the number of months in which the water reaches 21 °C (70 °F), the threshold we use for comfortable swimming for most people.
Key facts
- Longest swimming season (sea at 21 °C or more) among our complete sets of averages: Crete, 5 months out of 12.
- Warmest month for the water in the Mediterranean: August (23.8 °C / 75 °F in Ajaccio, 25 °C / 77 °F in Malta and Crete).
- Madeira has the most stable water temperature: 17 to 23 °C (63 to 73 °F), warmest in September.
- In the French West Indies (Guadeloupe, Martinique), the published water temperature exceeds 25 °C (77 °F) from February.
- Indicators (21 °C threshold, air-sea gap): Destination de Voyage calculation based on DWD averages, not official.
Average sea temperature, month by month
Values in °C (to convert to °F, multiply by 1.8 and add 32: 21 °C is 70 °F). A dash (–) marks a month we have not yet published for that destination. Click a column header to sort.
| Destination | Measuring point | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Months at 21 °C or more | Source of the average | Climate and best time to go |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Corsica | Ajaccio | 13.8 | 13.4 | 13.6 | 14.5 | 16.4 | 20.1 | 22.7 | 23.8 | 22.5 | 20.5 | 17.7 | 15.4 | 3 | Deutscher Wetterdienst (DWD), Ajaccio station | When to go to Corsica |
| Crete | Heraklion | 16 | 15 | 16 | 16 | 19 | 22 | 24 | 25 | 24 | 23 | 20 | 17 | 5 | DWD, Klimatafel for Heraklion | When to go to Crete |
| Malta | Luqa | 15 | 14 | 15 | 15 | 18 | 21 | 24 | 25 | 24 | 22 | 19 | 17 | 5 | DWD, Luqa station (water, 1946-1960) | When to go to Malta |
| Madeira | Funchal | 18 | 17 | 17 | 17 | 18 | 20 | 21 | 22 | 23 | 22 | 20 | 19 | 4 | DWD, Klimatafel for Funchal | When to go to Madeira |
| Cyprus | Larnaca | – | – | – | 18 | – | – | – | – | 26 | 24 | 21 | – | 3 (published months) | DWD, Klimatafel for Larnaca | When to go to Cyprus |
| Guadeloupe | Pointe-à-Pitre | – | 25 | – | 26 | – | – | – | – | – | – | – | – | 2 (published months) | DWD, Klimatafel for Pointe-à-Pitre | When to go to Guadeloupe |
| Martinique | Le Lamentin | – | – | 27 | 27 | 27 | – | – | – | – | – | – | – | 3 (published months) | DWD, Klimatafel for Le Lamentin | When to go to Martinique |
Air and sea: the surprising gap
| Destination | May (max air / sea) | Jun (max air / sea) | Jul (max air / sea) | Aug (max air / sea) | Sep (max air / sea) | Oct (max air / sea) |
|---|---|---|---|---|---|---|
| Corsica | 22.1 / 16.4 | 25.9 / 20.1 | 28.6 / 22.7 | 29.2 / 23.8 | 26.1 / 22.5 | 22.8 / 20.5 |
| Crete | 24.3 / 19.0 | 28.5 / 22.0 | 30.3 / 24.0 | 30.2 / 25.0 | 27.5 / 24.0 | 24.0 / 23.0 |
| Malta | 23.3 / 18.0 | 27.5 / 21.0 | 30.7 / 24.0 | 30.7 / 25.0 | 28.0 / 24.0 | 24.2 / 22.0 |
| Madeira | 22.0 / 18.0 | 23.7 / 20.0 | 25.4 / 21.0 | 26.8 / 22.0 | 26.6 / 23.0 | 25.2 / 22.0 |
From May to August, the maximum air temperature is 5 to 7 °C (9 to 13 °F) higher than the water in Corsica, Crete and Malta. In September and October the gap falls to 1 to 4 °C (2 to 7 °F): the air cools, but the sea keeps its summer warmth. In Madeira the gap stays between 2 and 5 °C (4 to 9 °F) all year. For swimming without the crowds, the end of the season is therefore often more attractive than the start.
Which plan suits you?
| Your plan | Where and when | Useful pages |
|---|---|---|
| Swimming from spring | French West Indies (25-27 °C / 77-81 °F from February to May) | when to go to Guadeloupe, Martinique in April |
| Warm sea in the Mediterranean | Malta and Crete from June to October, Corsica from July to September | when to go to Malta, when to go to Crete |
| Late-season swimming | Malta, Crete and Cyprus in October (22 to 24 °C / 72 to 75 °F) | Cyprus in October, Malta in October |
| Mild water all year, no heatwaves | Madeira (17 to 23 °C / 63 to 73 °F) | when to go to Madeira |
Looking for warm air rather than warm water? See our ranking of the warmest destinations each month.
Methodology
The water temperatures are those published in the DWD climate tables for a nearby coastal station, as reproduced on our climate pages (we do not estimate or interpolate any value). Where the source does not state the measurement period, we say so.
The « months at 21 °C or more » indicator counts the months whose average reaches this threshold, chosen by our editors. The air-sea gap compares the average maximum air temperature (normals from the national weather service, see each page) with the average water temperature; it is an order of magnitude only, as the two series do not cover the same period.
A monthly average is no substitute for the day’s reading: currents, wind and upwelling of cold water can change the water temperature by several degrees within a few days.
These values are a Destination de Voyage calculation: they are not official data. For today’s sea temperature, check a marine forecast service or the national weather service of the country. Our general verification approach is described on the methodology page.
Frequently asked questions
At what temperature can you swim?
There is no official threshold. Many swimmers find the water pleasant from 21 to 22 °C (70 to 72 °F); this is the threshold we use for our ranking.
When is the Mediterranean warmest?
In August, according to the DWD averages reproduced here: about 24 °C (75 °F) in Ajaccio and 25 °C (77 °F) in Malta and Crete. September is very close.
Where can you swim in warm water in winter?
Among the destinations we document, in the French West Indies: about 25 °C (77 °F) in February in Guadeloupe, according to the DWD.
Are these today’s temperatures?
No, these are climatological averages. For today’s temperature, consult a marine forecast service.
Why so few destinations?
We only publish a sea temperature if an official climatological source provides it. The list will grow as our climate pages are updated.
Our sources
- Deutscher Wetterdienst (DWD), Klimatafeln for the Ajaccio, Heraklion, Luqa, Funchal, Larnaca, Pointe-à-Pitre and Le Lamentin stations, as cited on our climate pages.
- Climate normals: the month-by-month climate tables on our when-to-go pages, each sourced from a national weather service or the WMO (organization and period shown under each table).
- Destination de Voyage climate pages (re-exported 14 October 2026).
- Our methodology
Updated October 2026.