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Brittany has a humid oceanic climate characterized by small variations in temperature, considerable rainfall, cool and mild summers and rainy winters. The climate of Brittany is often very variable with sudden changes, it goes from rain to sun in a few hours.
The influence of the Gulf Stream and the winds coming from the Atlantic Ocean means that the variations in temperatures between the various seasons are rather moderate. The winds are frequent and strong, and come mainly from the ocean.
The average minimum temperatures vary between 4°C in January and February and 13°C in August, while the average maximum temperatures vary between 9°C in January and over 20°C in July and August. In Brittany the sea water has temperatures varying between 18°C and 19°C in the months between July and September.
Southern Brittany is generally sunnier than northern Brittany, with over 2,000 hours of sunshine per year along the south coast. The rains are more abundant in the reliefs of the interior than along the coasts, in the monts d’Arrée and in the Montagne Noires there are averages of over 1,500 mm of rain per year, in the Rennes basin and along the coasts the annual average varies between 900 and 700 mm, with the exception of the Brest area, which records averages of over 1,100 mm of rainfall per year.
The rainiest months are those of autumn and winter, between October and February, while in spring and summer, rainfall drops considerably, especially between June and August.
WHEN TO GO TO BRITAIN?
The best time to visit Brittany is the summer, between June and August, but the months of May and September can also be good.
BRITAIN CLIMATE TABLES
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| BREST (51 m) | ||||
| Month | Average low (°C) | Average high (°C) | Rain (mm) | Rainy days |
| January | 4,2 | 9,1 | 138 | |
| February | 4,2 | 9,4 | 115 | |
| March | 5,1 | 11 | 97 | |
| April | 5,8 | 12,5 | 81 | |
| May | 8,5 | 15,6 | 72 | |
| June | 10,8 | 18,1 | 56 | |
| July | 12,8 | 20,4 | 50 | |
| August | 13,0 | 20,6 | 60 | |
| September | 11,4 | 18,7 | 89 | |
| October | 9,3 | 15,3 | 119 | |
| November | 6,5 | 11,9 | 121 | |
| December | 5,2 | 10 | 142 | |
| YEAR | 6,2 | 13,9 | 1140 |
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SEA WATER TEMPERATURE IN BRITAIN
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| BELLE ÎLE | |
| Month | Sea Water Temperature (°C) |
| January | 12 |
| February | 11 |
| March | 11 |
| April | 12 |
| May | 14 |
| June | 16 |
| July | 18 |
| August | 19 |
| September | 18 |
| October | 16 |
| November | 14 |
| December | 13 |
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