Rostrenen (; ) is a commune in the Côtes-d'Armor department and Brittany region of northwestern France.
Geography
Neighbouring communes
Rostrenen is border by Mellionnec to the south, Plouguernevel to the east, Kergrist-Moëlou to the north, and Glomel to the west.
Climate
Rostrenen has a oceanic climate (Köppen climate classification Cfb). The average annual temperature in Rostrenen is . The average annual rainfall is with January as the wettest month. The temperatures are highest on average in August, at around , and lowest in January, at around . The highest temperature ever recorded in Rostrenen was on 9 August 2003; the coldest temperature ever recorded was on 20 January 1963.
Population
In French the inhabitants of Rostrenen are known as Rostrenois.
Map
Breton language
On 13 September 2004 the municipality launched a linguistic plan as part of the Ya d'ar brezhoneg (Yes to Breton) campaign. In 2008, 34.5% of primary children attended bilingual schools.