Garmsir has a hot desert climate (KöppenBWh), characterised by little precipitation and high variation between summer and winter temperatures. The average temperature in Garmsir is 21.3 °C, while the annual precipitation averages 83 mm. July is the hottest month of the year with an average temperature of 33.8 °C. The coldest month January has an average temperature of 8.6 °C.
Garmsir was the scene of heavy fighting during April–September 2008 when U.S. Marines from the 24th MEU arrived to reinforce British and Afghan forces.