Rosalia is a small town located in the southeastern part of Washington state. It has a semi-arid climate, characterized by hot summers and cold winters. The average high temperature in the summer months hovers around 85°F (29°C), while winter temperatures can drop to around 30°F (-1°C). Precipitation is relatively low, with an average annual rainfall of around 18 inches (46 cm). Due to the arid climate, the town experiences high evaporation rates.

The hydrology constituents in Rosalia primarily consist of the Palouse River, which runs through the town. This river provides a vital water source for the community and supports local agriculture.

Rosalia offers various outdoor recreation opportunities. The surrounding area is known for its scenic beauty and offers opportunities for hiking, camping, and fishing. The nearby Steptoe Butte State Park provides stunning panoramic views of the Palouse region and is a popular spot for nature enthusiasts and photographers. The Palouse to Cascades State Park Trail, formerly known as the John Wayne Pioneer Trail, is also accessible from Rosalia, offering opportunities for biking, horseback riding, and hiking along its 253-mile route.