[2] Birkenfeld's post office was founded in 1916,[2] bringing much-needed mail service on a more local basis.

Degrees Minutes Seconds: Latitude: 45-59'26" N Longitude: 123-20'15" W Decimal Degrees: Latitude: 45.9906668 Longitude: -123.3376214 [6] Birkenfeld has a warm-summer Mediterranean climate (Köppen Csb) with cool and cloudy winters, and warm, dry summers.

[7] This climate is characterized by having overcast, wet, and changing weather conditions in fall, winter, and spring, as Birkenfeld lies in the direct path of the stormy westerly flow, and mild and dry summers when the Pacific High reaches in northernmost point in mid summer.

[8] According to the Köppen climate classification, Birkenfeld falls within the dry-summer temperate zone (Csb).

The coldest month is December with an average daily high of 44.0 °F (6.7 °C), although overnight lows usually remain above freezing by a few degrees.