Climate
Phoenix has an arid climate, which is characterized by some of the hottest seasonal temperatures experienced by any large city. In fact, out of the world's large urban areas, only some cities around the Persian Gulf, such as Riyadh, Saudi Arabia, and Baghdad, Iraq, have higher average summer temperatures. The temperature reaches or exceeds 100 °F (38 °C) on an average of 89 days during the year, including most days from early June through early September. On June 26, 1990, the temperature reached an all-time high of 122 °F (50 °C).[15] Low temperatures have shown a strong upward trend during the past three decades, likely due to the Urban Heat Island. Overnight lows greater than 90 °F (32 °C) occur with greater frequency every summer. The all-time highest low temperature was 96 °F (36 °C), which occurred on July 15, 2003.
The dry Arizona air makes the hot temperatures more tolerable early in the season, however, the influx of monsoonal moisture in July significantly raises moisture levels, but nowhere near the level that is experienced in other parts of the Sunbelt. On the other hand, the winter months are usually mild and sunny.
Phoenix sees some 300 sunny days per year. The average annual total at Phoenix Sky Harbor International Airport being 8.3 inches (210 mm). March is the wettest month of the year (1.07 inches or 27 mm) with May being the driest (0.09 inches or 2 mm). Although thunderstorms occur on occasion during every month of the year, they are most common during the monsoon from July to mid-September as humid air surges in from the Gulf of California. These can bring strong winds, large hail, or rarely tornadoes. Winter storms moving inland from the Pacific Ocean occasionally produce significant rains but occur infrequently. Fog is observed from time to time during the winter months.
Due to the Urban Heat Island effect, frost rarely occurs in the center of the city. The last time the temperature fell below 32 °F (0 °C) at the airport was January 15, 2007. The long-term mean date of the first frost is December 15 and the last is February 1; however, these dates do not represent the city as a whole because the frequency of freezes varies considerably among terrain types and elevations. Frequently, outlying areas of Phoenix will see frost, however, the airport does not. The earliest frost on record occurred on November 3, 1946, and the latest occurred on April 4, 1945. The all-time lowest temperature in Phoenix was recorded at 16 °F (-8.8 °C) on January 7, 1913.
Snow is extremely rare in the area. Snowfall was first officially recorded in 1896, and since then accumulations of 0.1 inches (0.25 cm) or greater have occurred only seven times. The heaviest snowstorm on record dates to January 20-21, 1937, when 1 to 4 inches fell (2 to 10 cm) in parts of the city and did not melt entirely for four days. Prior to that, 1 inch (2.5 cm) had fallen on January 20, 1933. On February 2, 1939, 0.5 inches (1 cm) fell. Most recently, 0.4 inches (1 cm) fell on December 21-22, 1990. Snow also fell on March 12, 1917 November 28, 1919, and December 11, 1985.[16]
Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Avg high °F (°C) 65 (18) 69 (21) 74 (23) 83 (28) 92 (33) 102 (39) 104 (40) 102 (39) 97 (36) 86 (30) 73 (23) 65 (18)
Avg low temperature °F (°C) 43 (6) 47 (8) 51 (11) 58 (14) 66 (19) 75 (24) 81 (27) 80 (27) 75 (24) 63 (17) 50 (10) 44 (7)
Phoenix is the hottest and second driest city in the United states, according to The Weather Channel's "Top 10", a program involving with ranking cities on criteria such as hottest, driest, coldest, wettest, windiest, sunniest, snowiest, and most humid.
Like Los Angeles and other autocentric American cities, the city's automobile-dependent nature holds implications for greenhouse gas emissions. Like most United States cities, its public transit system remains unused for the majority of passenger trips. Despite its MSA population being approximately one fifth that of New York City's, its public transit system accounts for just one percent of the passenger miles that New York City's does. [17]
Phoenix has an arid climate, which is characterized by some of the hottest seasonal temperatures experienced by any large city. In fact, out of the world's large urban areas, only some cities around the Persian Gulf, such as Riyadh, Saudi Arabia, and Baghdad, Iraq, have higher average summer temperatures. The temperature reaches or exceeds 100 °F (38 °C) on an average of 89 days during the year, including most days from early June through early September. On June 26, 1990, the temperature reached an all-time high of 122 °F (50 °C).[15] Low temperatures have shown a strong upward trend during the past three decades, likely due to the Urban Heat Island. Overnight lows greater than 90 °F (32 °C) occur with greater frequency every summer. The all-time highest low temperature was 96 °F (36 °C), which occurred on July 15, 2003.
The dry Arizona air makes the hot temperatures more tolerable early in the season, however, the influx of monsoonal moisture in July significantly raises moisture levels, but nowhere near the level that is experienced in other parts of the Sunbelt. On the other hand, the winter months are usually mild and sunny.
Phoenix sees some 300 sunny days per year. The average annual total at Phoenix Sky Harbor International Airport being 8.3 inches (210 mm). March is the wettest month of the year (1.07 inches or 27 mm) with May being the driest (0.09 inches or 2 mm). Although thunderstorms occur on occasion during every month of the year, they are most common during the monsoon from July to mid-September as humid air surges in from the Gulf of California. These can bring strong winds, large hail, or rarely tornadoes. Winter storms moving inland from the Pacific Ocean occasionally produce significant rains but occur infrequently. Fog is observed from time to time during the winter months.
Due to the Urban Heat Island effect, frost rarely occurs in the center of the city. The last time the temperature fell below 32 °F (0 °C) at the airport was January 15, 2007. The long-term mean date of the first frost is December 15 and the last is February 1; however, these dates do not represent the city as a whole because the frequency of freezes varies considerably among terrain types and elevations. Frequently, outlying areas of Phoenix will see frost, however, the airport does not. The earliest frost on record occurred on November 3, 1946, and the latest occurred on April 4, 1945. The all-time lowest temperature in Phoenix was recorded at 16 °F (-8.8 °C) on January 7, 1913.
Snow is extremely rare in the area. Snowfall was first officially recorded in 1896, and since then accumulations of 0.1 inches (0.25 cm) or greater have occurred only seven times. The heaviest snowstorm on record dates to January 20-21, 1937, when 1 to 4 inches fell (2 to 10 cm) in parts of the city and did not melt entirely for four days. Prior to that, 1 inch (2.5 cm) had fallen on January 20, 1933. On February 2, 1939, 0.5 inches (1 cm) fell. Most recently, 0.4 inches (1 cm) fell on December 21-22, 1990. Snow also fell on March 12, 1917 November 28, 1919, and December 11, 1985.[16]
Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Avg high °F (°C) 65 (18) 69 (21) 74 (23) 83 (28) 92 (33) 102 (39) 104 (40) 102 (39) 97 (36) 86 (30) 73 (23) 65 (18)
Avg low temperature °F (°C) 43 (6) 47 (8) 51 (11) 58 (14) 66 (19) 75 (24) 81 (27) 80 (27) 75 (24) 63 (17) 50 (10) 44 (7)
Phoenix is the hottest and second driest city in the United states, according to The Weather Channel's "Top 10", a program involving with ranking cities on criteria such as hottest, driest, coldest, wettest, windiest, sunniest, snowiest, and most humid.
Like Los Angeles and other autocentric American cities, the city's automobile-dependent nature holds implications for greenhouse gas emissions. Like most United States cities, its public transit system remains unused for the majority of passenger trips. Despite its MSA population being approximately one fifth that of New York City's, its public transit system accounts for just one percent of the passenger miles that New York City's does. [17]
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