Caulnes (French pronunciation: [kon] ⓘ; Breton: Kaon; Gallo: Caunn) is a commune in the Côtes-d'Armor department of Brittany in northwestern France.

The average annual rainfall is 848.4 mm (33.40 in) with November as the wettest month.

The temperatures are highest on average in August, at around 18.7 °C (65.7 °F), and lowest in January, at around 5.9 °C (42.6 °F).

Inhabitants of Caulnes are called Caulnais in French.

This Côtes-d'Armor geographical article is a stub.