Merrill, Oregon is a small town located in Klamath County, in the southern part of the state. The climate in Merrill is classified as semi-arid, with hot, dry summers and cold winters. Summers are typically sunny and warm, with temperatures often exceeding 90°F (32°C), while winters can be cold and snowy, with temperatures dropping below freezing.

The town is situated near the banks of the Lost River, which flows through the area. The hydrology constituents in Merrill are mainly influenced by the Lost River and its tributaries. The water from these sources supports agricultural activities in the region, including irrigation for farms and ranches.

Merrill offers several outdoor recreation opportunities for nature enthusiasts. The Lost River and its nearby reservoirs provide opportunities for fishing, boating, and water sports. The surrounding areas also offer ample opportunities for hiking, camping, and wildlife viewing. The nearby Lower Klamath National Wildlife Refuge is a popular destination for birdwatching, with over 350 species of birds recorded in the area.

Overall, Merrill, Oregon offers a semi-arid climate, with a focus on the Lost River and its hydrology constituents, providing various outdoor recreation opportunities for visitors and residents alike.