The township has a hot-summer humid continental climate (Dfa) and is in hardiness zone 6b. The average monthly temperature in Barto ranges from 29.4 °F in January to 74.2 °F in July.[3]
As of the census[4] of 2000, there were 3,354 people, 1,212 households, and 970 families living in the township. The population density was 239.2 inhabitants per square mile (92.4/km2). There were 1,250 housing units at an average density of 89.2 per square mile (34.4/km2). The racial makeup of the township was 97.88% White, 0.75% African American, 0.09% Native American, 0.33% Asian, 0.24% from other races, and 0.72% from two or more races. Hispanic or Latino of any race were 0.66% of the population.
There were 1,212 households, out of which 35.6% had children under the age of 18 living with them, 70.5% were married couples living together, 6.0% had a female householder with no husband present, and 19.9% were non-families. 15.1% of all households were made up of individuals, and 6.0% had someone living alone who was 65 years of age or older. The average household size was 2.77 and the average family size was 3.08.
In the township the population was spread out, with 25.8% under the age of 18, 6.1% from 18 to 24, 30.8% from 25 to 44, 25.8% from 45 to 64, and 11.5% who were 65 years of age or older. The median age was 38 years. For every 100 females there were 104.8 males. For every 100 females age 18 and over, there were 103.7 males.
The median income for a household in the township was $53,241, and the median income for a family was $60,054. Males had a median income of $37,951 versus $26,298 for females. The per capita income for the township was $20,454. About 2.1% of families and 3.0% of the population were below the poverty line, including 2.3% of those under age 18 and 2.1% of those age 65 or over.
As of 2019, there were 46.55 miles (74.91 km) of public roads in Washington Township, of which 13.51 miles (21.74 km) were maintained by the Pennsylvania Department of Transportation (PennDOT) and 33.04 miles (53.17 km) were maintained by the township.[7]
Pennsylvania Route 100 crosses Washington Township north-to-south on its path from Lehigh County to Pottstown via Bally. Other local roads of note include Barto Road, County Line Road, Forgedale Road, Hoffmansville Road, Old Route 100, and Niantic Road.
