Phoenix has a hot desert climate (Köppen: BWh) and holds the distinction of being the largest city in the Americas within this climatic zone, while receiving a staggering 3,872 hours of sunshine annually—more than any other major city on Earth. Summers are brutally hot, with an average of 111 days per year exceeding 100°F (38°C) and an all-time record high of 122°F (50°C) set on June 26, 1990. Due to the urban heat island effect, the city experiences unusually warm nights for a desert, with an average of 74 summer nights staying at or above 80°F, culminating in a record warm daily low of 97°F on July 19, 2023. Rainfall is scarce (just 7.22 inches annually), but the North American monsoon (officially recognized from June 15 to September 30 since 2008) can trigger flash floods and dust storms—such as the remnants of Hurricane Norbert, which dropped a record 3.30 inches on September 8, 2014. Air quality is a notable issue, as Phoenix ranks fifth in the US for ozone pollution, and high levels of particulate matter increase the risk of Valley Fever, a fungal lung infection. Finally, desert lands around the city are highly susceptible to wildfires, particularly in dry spring and summer months following wet winters, posing a growing seasonal hazard.