Arreau (French pronunciation: [aʁo]; Occitan: Àrreu) is a commune in the Hautes-Pyrénées department in southwestern France.

The average annual temperature in Arreau is 9.6 °C (49.3 °F).

The average annual rainfall is 894.8 mm (35.23 in) with November as the wettest month.

The temperatures are highest on average in July, at around 17.6 °C (63.7 °F), and lowest in January, at around 2.0 °C (35.6 °F).

This Hautes-Pyrénées geographical article is a stub.