Murrieta, California, covers an area of 33.6 square miles, as reported by the United States Census Bureau. Of this expanse, 99.89% is land, while 0.11% is water. The city's landscape is traversed by Murrieta Creek, which flows southeasterly through the Murrieta Valley, accompanied by its tributary, Warm Springs Creek.

Murrieta enjoys a Mediterranean climate, classified as dry-summer subtropical (Köppen Csa). The city experiences an average of 263 sunny days and 35 days with measurable precipitation annually. From April through November, the weather is predominantly warm to hot and dry, with average high temperatures ranging from 77°F to 91°F (25°C to 33°C), and lows from 48°F to 60°F (9°C to 16°C). The November to March period is characterized by milder temperatures and occasional rainfall.

The city's microclimate results in temperature variations of up to 18°F (10°C) between inland areas and the coast, with a gradient of 1°F per mile (0.3°C/km) moving inland. Murrieta receives an average of 31 days of precipitation per year, totaling approximately 16 inches (410 millimeters) annually. This precipitation primarily occurs during the winter and spring months (November through April), typically as light rain showers but occasionally as heavy rainfall and thunderstorms. While snowfall is rare in the city basin, the surrounding mountain slopes often see snowfall each winter.

Overall, Murrieta's geography and climate make it a city of warm, sunny days and mild, wet winters, providing a pleasant environment for residents and visitors alike.