Climate of Houston

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The Climate of Houston is classified as humid subtropical. Houston's warmest month (on average) is July at 85 °F (29 °C), and the coldest month being January at 54 °F (12 °C). The average yearly precipitation level is 54 inches (1,400 mm). Houston has occasional severe weather, mostly in the form of flooding. Spring supercell thunderstorms sometimes bring tornadoes to the area. Houston experiences tropical cyclones during the hurricane season, which can bring significant damage to the city. Houston's air is polluted by ozone and other chemicals that pose definite health risks.[1]

Contents

[edit] Seasonal observation

Weather averages for Houston
Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
Record high °F (°C) 85 (29) 87 (31) 96 (36) 94 (34) 98 (37) 101 (38) 104 (40) 106 (41) 101 (38) 96 (36) 90 (32) 84 (29) 106 (41)
Average high °F (°C) 63 (17) 67 (19) 74 (23) 79 (26) 86 (30) 91 (33) 94 (34) 93 (34) 89 (32) 82 (28) 73 (23) 65 (18) 80 (27)
Average low °F (°C) 45 (7) 48 (9) 55 (13) 61 (16) 68 (20) 74 (23) 75 (24) 75 (24) 72 (22) 62 (17) 53 (12) 47 (8) 61 (16)
Record low °F (°C) 10 (-12) 14 (-10) 22 (-6) 22 (-6) 44 (7) 56 (13) 45 (7) 64 (18) 50 (10) 33 (1) 25 (-4) 9 (-13) 9 (-13)
Precipitation inches (mm) 4.3 (109.2) 3.0 (76.2) 3.2 (81.3) 3.5 (88.9) 5.1 (129.5) 6.8 (172.7) 4.4 (111.8) 4.5 (114.3) 5.6 (142.2) 5.3 (134.6) 4.5 (114.3) 3.8 (96.5) 54.0 (1,371.6)
Source: weather.com[2] Aug 2007

[edit] Summer

The summer months in Houston are hot and humid, with occasional afternoon thunderstorms. The average daily high temperature peaks at 94 °F (34 °C) at the end of July,[3] with an average of 99 days per year above 90 °F (32 °C).[4] The average relative humidity ranges from over 90 percent in the morning to around 60 percent in the afternoon.[5] These values of relative humidity results in a heat index higher than the actual temperature.[6] The hottest temperature ever recorded in Houston was 109 °F (43 °C) on September 4, 2000.[7] Heat stroke can strike people who stay out of doors for long periods of time during the summer.[8] Houston's heat and humidity made air-conditioning an essential element in Houston's early survival, and it continues to be important in day-to-day life.[9] Air conditioning is considered the stimulus for the growth of Houston in 1950 when it became the most air-conditioned city in the world.[10] Tropical cyclones can move into the area anytime during the summer months, bringing heavy rainfall.[11]

[edit] Autumn

Autumn in Houston is fairly mild, with temperatures averaging near 79 °F (26 °C) during the day and 52 °F (11 °C) at night. [12] Cold fronts which move through the region during the fall can bring heavy, flooding rains, with floods most frequent throughout October and November.[13] Tropical cyclones move into the area from both the Gulf of Mexico and the eastern Pacific ocean through October. Since 1851, the latest a tropical cyclone has impacted Texas from the Gulf of Mexico was Hurricane Juan (1985), on October 28 of that year.[14]

[edit] Winter

Winters in Houston are mild and fairly temperate. While the average high in January, the coldest month, is 61 °F (16 °C), Houston sees an average of 18 days per year of 32 °F (0 °C) temperatures or less.[15] The coldest temperature ever recorded in Houston was 5 °F (−15 °C) on January 23, 1930.

Throughout December, strong southward-moving cold fronts, called "blue northers," [16] batter the city with cold rain, low wind chills, freezing rain, and sometimes frozen precipitation. Early January is the coldest time of the year, with temperatures moderating by February.

[edit] Snow and ice

December 24th Snowstorm, shown on satellite.
December 24th Snowstorm, shown on satellite.

Snow is unusual in Houston, with an event occurring nearly every 4 years. Snow has fallen approximately 30 times since 1895,[17] most recently on December 24, 2004 which was the first time snow fell on Houston during Christmas Eve. Snow was also expected for Christmas Day, but did not accumulate. Freezing rain events, also known as ice storms, can cause heavy damage to traffic, and can close schools and businesses. The most recent ice storms occurred in 1997 and 2007.

[edit] Spring

Spring comes with a very mild warm up from winter, lasting from March 20 through May. Temperatures stay fairly low, not usually warming up above 77 °F (25 °C). Often during spring, supercell thunderstorms can occur, [18] prompting Houston's 10-month long "growing season" to begin. Spring also sees the return of many animals, including butterflies and mosquitoes, to return to Houston's infamous warm climate.

Spring slowly diminishes the colder winter temperatures, yet freezing weather can still occur on some nights in late March.

[edit] Precipitation

Rainfall is the most common form of precipitation in Houston. The wettest month is May, with 5.6 inches (140 mm) of rain. The city receives 47.9 inches (1,220 mm) of rain in an average year. The most precipitation to fall in one year was 72.86 inches (1,851 mm) which occurred in 1900. Houston has received less than 20 inches (510 mm) of rain only once: 17.66 inches in 1917.[19] Flash flood warnings are common all year, and due to the flat landscape, heavy rains can be a threat to the city.

Sleet, snow and ice are unusual, and sometimes never occur at all during the winter. Hail can accumulate, yet only in small quantities. Frozen precipitation does not survive the warmer temperatures.

[edit] Extreme weather

Houston has occasional severe weather, mostly in the form of flooding. The effects of tropical cyclone landfall can bring severe damage to the city and region.

[edit] Tropical storms

Because of Houston's close proximity to the Gulf of Mexico, the city has a significant chance of receiving hurricanes and tropical storms every hurricane season.

Houston's history of hurricanes stretches back to 1837, when the Racer's Storm passed just to the south of the town, raising water levels four feet.[20] The Great Hurricane of 1900, which razed nearby Galveston, also passed over Houston, but the hurricane weakened to a tropical storm by the time it reached Houston.[21] The periphery of Hurricane Carla affected the city in 1961, causing major damage to Houston. At the time of landfall, Carla was the most powerful tropical system to affect the Texas coast in over 40 years,[22] and many would follow its destructive path. In 1983, the city experienced a direct hit in the form of Hurricane Alicia, causing one billion dollars damage to the city and striking during a down period in the city's economy.

The most destructive and costly natural disaster in city history was Tropical Storm Allison of 2001, [23] which dumped up to 37 inches (940 mm) of rain on parts of the city over a 5-day period. The storm completely overwhelmed the area's flood control system and caused $6.05 billion (2006 USD) damage. It is the only tropical storm in history to have its name retired.

Tropical Storm Erin made landfall on the Texas coast in August 2007, and struck Houston with strong rains. A total of 9 inches (230 mm) of rain fell at George Bush Intercontinental Airport on August 16, 2007, and many roads and neighborhoods were flooded. METRO halted its light rail and bus services in view of the effects. The storm did fatal damage to a Randall's grocery store in Clear Lake, where its roof collapsed, killing one and injuring another. Another three deaths were reported throughout the city, and the Houston Fire Department reported 72 rescue operations. A total of 4 deaths were caused by the storm.

[edit] Flooding

Flooding is a major threat all year in Houston, particularly in fall and winter. The marshland around Houston easily floods, due to its low elevation. In fall, strong cold fronts batter the city, and flooding regularly happens. Many bayous in the city are adjacent to low-lying sections of the city, posing a threat of overflow and flood damage to many homes and businesses. Additionally, many of the city's older suburbs have outdated sewer systems, which can't drain water in the event of flash flooding.

[edit] Tornadoes

Unlike much of Texas, Houston is not considered a part of Tornado Alley, but smaller tornadoes are common during severe weather. They are most likely to be found along frontal boundaries of an air mass during the spring months. The most common tornadoes in Houston measure F1 on the old Fujita scale, which can destroy or damage one or two buildings. The strongest recorded tornado in Houston history was an F4 on November 21, 1992, part of a large outbreak of tornadoes. [24]

[edit] Environmental issues

Houston is well-known for its polluted environment. Harris County alone is home to 15 Environmental Protection Agency Superfund sites, more than any other area in Texas. The list contains numerous companies, streets and waterways that have been considered dangerous to humans.[25] The city suffers from smog quite often, and many of the city's bayous are coated with trash and other debris. Since its founding, Houston has also seen rising temperatures, with new heat records occurring every year.

[edit] Air pollution

Houston is well known for its oil and petrochemical industries, which are leading contributors to the city's economy. The industries located along the ship channel, [26] coupled with a growing population, has caused a considerable increase in air pollution for the city each year. Houston has excessive ozone levels and is ranked among the most ozone-polluted cities in the United States.[27] Ground-level ozone, or smog, is Houston’s predominant air pollution problem. In 2000, Houston earned the title of "most polluted city in America" by its standards and was ordered by the federal government to clean up pollution by 2007. [28][29] A 2007 assessment found the following twelve air pollutants to be definite risks to health in Houston:[1]

The State of Texas concluded that, since 2000, the Manchester area in eastern Houston had the highest annual averages of 1,3-Butadiene of any area in Texas.[30]

Houston has introduced many programs since the 2000 federal order to reduce air pollution in the city.[citation needed] The most notable project was the METRORail light rail system constructed in 2004. The light rail system was designed to encourage Houstonians to utilize public transportation instead of their automobiles.

[edit] Water pollution

Houston has also seen recent improvements to the city's waterways. The banks of Buffalo Bayou have been cleaned of garbage and have been turned into jogging trails and parks. Since the mid-1990s, Houston has seen a great increase in wildlife along the bayou due to many successful cleaning attempts.[31] The Port of Houston has not seen any major cleaning attempts and continues to be polluted from the local refineries and industries.

[edit] Global warming

Global warming is a potential factor in the city's weather. Houston often sees ozone damage from both pollution and global warming. Six of Houston's hottest recorded temperatures have been since 1986.[32] The warmest, in 2000, was 109 °F (43 °C).

[edit] Notes

  1. ^ a b Sexton K, Linder SH, Marko D, Bethel H, Lupo PJ (2007). "Comparative assessment of air pollution-related health risks in Houston". Environ Health Perspect 115 (10): 1388–93. doi:10.1289/ehp.10043. PMID 17938725. 
  2. ^ Weather.com: Weather Channel Historical Weather for Houston, Texas, United States of America. Retrieved on Aug 3, 2007.
  3. ^ Weather Channel. Monthly Averages for Houston, Texas. Retrieved on 2007-03-10.
  4. ^ United States Department of Commerce. National Climatic Data Center. Retrieved on 2007-03-10.
  5. ^ Department of Meteorology at the University of Utah. National Relative Humidity. Retrieved on 2007-03-10.
  6. ^ Your Florida Backyard. The Heat Index. Retrieved on 2008-03-20.
  7. ^ Weather Underground. History for Houston Intercontinental, Texas on Monday, September 4, 2000. Retrieved on 2007-03-10.
  8. ^ Texas Medical Center News. Temperature Rising? Could be Heat Stroke. Retrieved on 2007-03-11.
  9. ^ The Old House Web How Air Conditioning Changed America. Retrieved on 2007-03-11.
  10. ^ Houston Geological Auxiliary. A Short History. Retrieved on 2007-03-11.
  11. ^ David M. Roth. Tropical Cyclone Rainfall for the Gulf Coast. Retrieved on 2008-03-20.
  12. ^ Greater Houston Partnership. Information/Data — All About Houston. Retrieved on 2006-01-09.
  13. ^ Weather Research Center. Significant Houston Area Floods. Retrieved on 2006-01-09.
  14. ^ National Hurricane Center. Atlantic Hurricane Database. Retrieved on 2008-03-20.
  15. ^ National Climatic Data Center. U.S. Department of Commerce, Retrieved on 2007-03-10.
  16. ^ TSHA Handbook of Texas. Blue Norther. Retrieved on 2007-03-11.
  17. ^ Weather Research Center. Houston Snow. Retrieved on 2006-01-09.
  18. ^ Severe Thunderstorms. National Weather Service Forecast Office Houston/Galveston, Texas, Retrieved on March 11, 2007
  19. ^ Houston's Annual Topn 10 List. National Weather Service, Houston/Galveston, Texas. January 30, 2006. Last accessed January 3, 2006.
  20. ^ http://www.srh.noaa.gov/lch/research/txearly19hur.php Early Texas Hurricane History, 1800-1850, Retrieved on March 10, 2007
  21. ^ Remembering the Great Hurricane, September 8, 1900. Galveston County Daily News, Retrieved on March 11, 2007
  22. ^ Hurricane Carla, September 9-12, 1961. National Weather Service, Retrieved on March 11, 2007
  23. ^ [http://www.srh.noaa.gov/hgx/projects/allison01.htm Tropical Storm Allison Floods June 5-9, 2001]. National Weather Service Forecast Office Houston/Galveston, Texas, Retrieved on March 11, 2007
  24. ^ Cluster Tornado Outbreak in Houston, TX. Stormtrack Library, Retrieved on March 10, 2007.
  25. ^ The EPA's Superfund list for Texas
  26. ^ "Summary of the Issues", Citizens League for Environmental Action Now , 2004-08-01. Retrieved on 2006-02-17.
  27. ^ "State of the Air 2005, National and Regional Analysis ", American Lung Association, 2005-03-25. Retrieved on 2006-02-17.
  28. ^ "Catching Our Breath", The University of Texas at Austin. Retrieved on 2006-02-17.
  29. ^ Lonely Planet Guide to Texas, page 304
  30. ^ "State Results: Pollution Glance." Houston Chronicle.
  31. ^ Texas Monthly Guide to Houston Edition 1996 ISBN 0-87719-272-3 Pg. 9-10.
  32. ^ Weatherbase. Historical Weather for Houston. Retrieved 2007-03-11.

[edit] External links