Perth, Australia, enjoys a hot-summer Mediterranean climate (Köppen Csa), characterized by distinct seasonal changes and plenty of sunshine. Summers in Perth are typically hot, dry, and sunny, lasting from December to March, with February being the hottest month. Temperatures frequently soar above 35°C (95°F), and on average, the city experiences 26 days per year with temperatures exceeding 35°C, while 5 days a year see temperatures surpass 40°C (104°F). The highest temperature ever recorded was a sweltering 46.2°C (115.2°F) in February 1991. Despite the heat, a refreshing sea breeze known as the "Fremantle Doctor" often provides relief in the afternoon, lowering temperatures significantly after its arrival.

Winters, on the other hand, are relatively mild and wet, with the majority of Perth’s annual rainfall occurring between May and September. Rainfall comes in the form of frontal systems moving across the region, and while the city experiences significant rainfall during this period, it’s often interspersed with clear, sunny days. During winter, minimum temperatures can dip below 5°C (41°F), though freezing temperatures are rare. The lowest recorded temperature in Perth was −0.7°C (30.7°F) in June 2006, while the coldest temperature in the metropolitan area reached −3.4°C (25.9°F) at Jandakot Airport. While snowfall is extremely rare, light snow has been reported in the Perth Hills, with the most recent snowfall occurring in 1968.

Perth is known for its abundant sunshine, averaging 8.8 hours of sunshine per day, translating to around 3,200 hours of sunshine annually. This makes Perth the sunniest capital city in Australia, with 138.7 clear days each year. However, in recent decades, Perth has witnessed a noticeable shift in its rainfall patterns. Since the mid-1970s, there has been a significant decrease in winter rainfall, while summer has seen an increase in extreme rainfall events. Notable storms, such as the slow-moving storms in 1992, tropical lows in 2017, and remnants of ex-Tropical Cyclone Joyce in 2018, have brought heavy rainfall to the region, with some storms dropping over 100 millimeters (4 inches) of rain in just a few hours. Additionally, severe thunderstorms and large hail have caused significant damage, highlighting the city’s unpredictable weather.