Los Nietos is a small unincorporated community located in Los Angeles County, California. Situated in Southern California, Los Nietos experiences a Mediterranean climate, characterized by mild, wet winters and warm, dry summers. The average temperature ranges from the mid-60s°F (18-20°C) in winter to the mid-80s°F (29-32°C) in summer. While rain occurs mainly in the winter months, the area enjoys about 300 days of sunshine per year.

Hydrologically, Los Nietos is part of the larger Los Angeles River watershed. However, being an urbanized area, it lacks prominent water bodies within its boundaries. Residents primarily rely on imported water sources.

Despite its urban nature, Los Nietos offers some outdoor recreation opportunities. The nearby Whittier Narrows Recreation Area provides a variety of activities, including hiking, picnicking, fishing, and bird-watching. The park also features golf courses, soccer fields, and horseback riding facilities. For nature enthusiasts, the Rio Hondo Bike Path offers a scenic route along the river for walking, jogging, or cycling. Additionally, several parks within the community offer open spaces for recreational activities and sports.