Climate of Finistere

The climate of the Finistere shows the characteristic of a oceanic moderate climate under the influence of the Gulf Stream and the Atlantic disturbances. It is characterized by soft winters and fresh summers. Precipitations are spread out over all the year, they increase appreciably inside the grounds and on the relief. The frosts are rare, the presence of the wind is another characteristic of this climate.

Evolution of the climate

The Climat is a characteristic which evolves/moves in time. Without returning to the Ice Age, or even to the Small Age Ice occurred under the reign of Louis XIV, we live today a Climate change whose amplitude is higher than the climatic differences which exist between two close departments. Thus, during last century the isothermal S in France progressed overall towards the north of approximately 150 kilometers. Thus the number of days when the temperature exceeded 25 ° a.c. increased on average of more than 50% in Toulouse of 1950 to 2000.

The presentation of absolute figures thus has only little direction concerning the climate of a department. There is more direction to compare the values with those of other departments, and even inside the department.

A juxtaposition of microclimates

With a length of coast largely higher than any other French department (1250 km out of the 5500 km of the Littoral French), and no point of the department located at more than 50 km of the sea, Finistere can only have one soft and rainy climate. But while looking in the details one realizes that its geography involves relatively important variations between:

heights of the interior, Mounts of Arrée and Black Mountains, which exceeds 300 m of altitude, and that one calls in Brittany rear carry out (the mountain),
the plates which surrounds them (Armorican peneplain), whose altitude varies little around 50 to 80 m of altitude, that one also calls by places rear carry out by deformation of rear maezh (the countryside) but also to mark an important difference with:
a coastal strip of a few hundred meters to a few kilometers, who materializes in a spectacular way when snow covers (seldom) the remainder of the department whereas it melts instantaneously by touching the ground close to the coast. It is also necessary to distinguish:

between the Coast-with Armor and Plouarzel, a low coast directed in the North, where the breaks thermal is translated into summer by a wind of North supported during the day and the relatively calm nights,
between the Morbihan and Audierne, a low coast directed in the South, where the thermal breeze is translated into summer by a moderate wind of South during the day and North during the night,
between Audierne and Plouarzel, a traversed zone of current violent one which twice a day bring fresh water of the Manche and water more tepid of the the Bay of Biscay in contact with masses of air saturated with moisture, thus causing very dense Fog S sometimes; this zone even comprises it:

a line of high cliffs, in front of the plates of the Leon, the peninsula of Crozon, and of the Cornwall, which accelerate the speed of the wind and increase there the pluviometry,
with broad, the plate of Ushant of which the cliffs have the same effect, while receiving full whip the swell of the Atlantic,
between the two, of many islands which are only sand banks, too low to hang the clouds,
and behind the two vast notches of the Rade of Brest and bay of Douarnenez , which benefits from the lenitive influence of the sea without undergoing the full force of the storms of winter.

Comparative data

Temperatures

The minimal average temperatures in January vary 2° in the mountain with 7° with Ushant, value which is exceeded in France only in the Corsica Cape.

The maximum average temperatures in July vary from 18 with 20° according to the places, that is to say 4 with 5° in lower part of the French average.

The number of days with frosts varies of more than 30 in the mountain with 3 in Ushant, to compare with more than 50 in Île-de-France or with Tarbes and 80 with Strasbourg.

On average no day ago without thaw in Finistere, against 6 with Paris or Limoges.

The number of days when the temperature exceeds 25° varies from 0 in Ushant with less than 10 in the interior of Finistere, against 15 in the Somme and more than 90 with Perpignan or Marseilles. There is on average 1 day per annum where the temperature exceeds 30° in the interior, against 3 in the Sum and more than 30 with Nimes.

The extreme temperatures recorded with Brest (station of Brest-Guipavas) between 1945 and 2001 are respectively of +35,2°C on July 12th 1949 and -14°C on January 28th 1947. One can compare them with the -11°C Biarritz and Perpignan (1963) and with the +34 of Boulogne-sur-Mer and Dieppe in 1955. In Ushant the variation is not any more but of -6° with +29°.

Sunning

The number of hours of sun varies from 1600 in the mountain with more than 2000 on the southern part, but, except these extremes, the 1750 hour old curve merges almost with the parallel which Brest joint in Colmar.

The percentage of sunny hours in July varies from less than 45% in the mountain, quantifies that one finds only in the Nord-Pas-de-Calais, with nearly 55% on the southern part, quantifies higher than that of the Pays Basque and than a great northern half of France.

The percentage of sunny hours in December varies from 18 on the northern coast with nearly 25 on the southern part, in accordance with the whole of France to this latitude.

The number of days per annum without sun varies of almost 60 on the northern coast with less than 50 on the southern part, to compare with 80 in Strasbourg, 66 in Paris, nearly 60 in Limoges, Lyon or Grenoble, and 21 in Marseilles.

In summer the sun lies down more than one hour and quarter later in Brest that in Bastia (Corsica), whereas it rises only half an hour later. In winter it rises more than one hour and quarter later to Brest that to Bastia, whereas it lies down only half an hour later.

Rain

It falls more than 140 cm from water per annum in the mountain, quantifies which corresponds to the other French reliefs, against less than 70 on the west coast, quantifies which corresponds to most of France, coasts Mediterranean and Corsican included/understood. Even with small scales variability is very important, thus the airport of Brest located on the commune bordering on Guipavas, but to 98 m of altitude, receives 116 cm of water compared with 79 in the city, to a few hundred meters of the sea and with a score of meters of altitude.

The number of days of rain varies of more than 200 in the mountain, which is a national record, with 160 on the southern part, as in Dunkirk, Paris, Lyon or Tarbes.

The numbers of days with important rain (more than 5 l/m2) varies of more than 80 in the mountain, which is a national record, with 50 on the coast, as in Cognac, Agen, Lyon or Nancy. In summer, the figures are of less than 20 in the mountain (only the solid mass of the Jura is sprinkled more), and of less than 10 on the southern part (only the Mediterranean coast is sprinkled).

The number of days of snow varies from ten in the mountain, quantifies everywhere exceeded in the east of a line Cherbourg Carcassonne, to 3 on the coasts, as the island of Yeu, Montpellier, Nice or Perpignan.

The number of days of storm varies from about fifteen in the mountain, quantifies similar to that of Normandy and appreciably lower than that of the northern half of France, to 3 on the southern part, quantifies which is beaten only by the Corsica Cape.

The number of day of fog varies of more than 100 in the mountain, quantifies which is beaten only by Castle-Chinon and Mount-with-Marsan, with more than 50 on the west coast, and less than 30 on the coasts north and south, which is appreciably lower than the French average, only the Alps and the Mediterranean region knowing of the definitely lower figures.

Wind

As well of mean velocity as expressed as a percentage of been windy hours (with more 23km/h or forces 4) only Toulon, with 19 km/h and 37%, is been windy more than Brest, with 18 km/h and 32%. In the same way only the semaphore of the Cape of La Hague, with 51% of been windy hours, is more than that of Ushant, with 49% and one mean velocity of 26 km/h. On the other hand the number of days with strong wind (more than 57 km/h or force 7) does not have anything exceptional, Brest, with 76 days, is far behind Toulon, with 119 days, and the Rhone-native corridor, and even Cambrai (95) or Castle-Chinon (82).

Statistics

Average temperatures:

January: 6°C
July: 18°C.

The two following tables gather average annual statistics for Île of Ushant and Penmarc' H.

These data, coming according to any probability of the weather stations from these two sites going back to 1991.

See source on German Wikipédia: .

Caution: The concepts of very sunny days or with overcast sky is very subjective, according to the countries of the interpreter of the figures.

Station: island of Ushant, altitude: sea level. Described the climate of northern Finistere, with strong weighting of the oceanic influence

Many days with:

Precipitations of more than 1 mm: 127
Freezing: 3
Snow: 4
Storm: 5
Hail: 5.

Described the climate of southern Finistere, with strong weighting of the oceanic influence

Weather station of Penmarc' H between Audierne and Pont-l'Abbé with the sea level, located at the south of the department.

Many days with:

Precipitations of more than 1 mm: 115
Freezing: 10
Snow: 1
Storm: 4
Hail: 2.

Extremum

Station of Brest-Guipavas for the period 1945 - 2001:

the lowest Temperature: -14 °C on January 28th, 1947
the highest Temperature: 35,2 °C on July 12th, 1949
the coldest Year: 1963
the hottest Year: 1989
the driest Year: 1953
the most rainy Year: 1960
the wettest Day: 56,4 mm on August 5th, 1962 (in 24:00)

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