Climate of Houston

Severe weather of Houston mostly takes the form of flooding, which occurs most commonly between May and October, the city's monsoon season.

Houston sometimes experiences tropical cyclones during the Atlantic hurricane season, which can bring heavy rain and significant damage to the city.

However, during El Nino or La Nina years the wet and dry season can often either last longer than usual or be delayed.

[14] Because of the high temperatures that persist in the months of April through October, most indoor workers in Houston spend the hottest part of the day in an air-conditioned environment.

March sees the return of many types of insects, including butterflies and mosquitoes, to Houston's warm climate.

[1] The city (and much of South and Southeast Texas) has its own irregular monsoon season, which usually lasts from May to October, but sometimes April to September.

[22] Flash flood warnings are common all year, and due to the flat landscape, heavy rains often threaten life and property in the city.

Sea breeze showers which are monsoon-like (especially during the summer months, originating from the mesoscale convective cycle, where the polar jet stream usually forms an omega block) are common throughout the Texas Gulf Coast area (from Brownsville to the Florida Peninsula), which has a similar climate to areas like Mumbai and Kolkata – locals refer to the sea breeze showers as the Gulf Coast Monsoon (also called the Gulf of Mexico or the Texas Monsoon), despite Houston being 50 feet above sea level.

[24] The Great Hurricane of 1900 destroyed the nearby (and then much bigger) city of Galveston, which is situated on a barrier island 50 mi (80 km) southeast of downtown Houston.

Tropical Storm Allison dumped up to 37 inches (940 mm) of rain on parts of the city over a five-day period in 2001, and was the most destructive and costly natural disaster in Houston history[27] prior to Hurricane Harvey.

The storm completely overwhelmed the flood control system and caused 22 deaths in Houston and $6.05 billion (2006 USD) in damage.

A total of 9 inches (230 mm) of rain fell elsewhere than George Bush Intercontinental Airport on August 16, and many roads and neighborhoods were flooded.

Metropolitan Transit Authority of Harris County, Texas, halted its light rail and bus services in view of the effects.

Ike brought moderate rain but high winds for an unusually long duration (upwards of nine hours).

The area is drained by a network of bayous (small, slow-moving rivers, often dredged and enlarged to increase volume) and man-made drainage ditches, which are usually dry most of the year.

However, occasionally very heavy thunderstorms dump so much water on the city that widespread congestion and even property damage in low-lying areas result.

In late August 2017, Hurricane Harvey flooded Houston, causing severe widespread damage and at least 14 deaths.

Tornadoes in Houston usually measure a weak EF1 on the Enhanced Fujita scale and cause light to moderate damage to well-constructed buildings.

In descending order of frequency, the most snow has fallen in January, followed by February, December, November, and finally a single occurrence on March 10, 1932,[40] which was also the lowest recorded temperature for that month, 22 °F (−6 °C).

These storms can be very disruptive since road crews are not equipped to handle such rare events over the city's expansive size.

[43][44] The city's Office of Emergency Management encourages driver's to "avoid driving unless absolutely necessary... if roadways are at risk of icing.

[46] The ice storm that occurred on January 16, 2018, started as cold rain for several hours, before changing to a wintry mix and then eventually sleet and snow.

Temperatures started in the low-mid 30s and quickly dropped to the 20s in the afternoon, before dipping into the teens by the evening/overnight hours, which caused all the rain to turn to ice, accumulating a thickness up to 1" on some roads, bridges, overpasses, making it one of the worst winter storms in the history of the state.

The Winter Storm of February 15, 2021 was a very dangerous & devastating one for the Houston area, starting out mainly as freezing rain with a few flakes or sleet pellets mixing in at times, then transitioning into moderate/heavy sleet during the evening and finally changing over to snow overnight bringing anywhere between 1-4" inches of snow throughout the Houston area on top of a layer of ice/sleet, there were widespread power outages throughout the majority of the state including Houston/Harris County.

The chance of damage from tropical storms and hurricanes also goes up during La Niña events, due to decreased Atlantic wind shear.

Post-El Niño weather during the spring usually result in increased rainfall, as demonstrated during the Memorial Day 2015 and Tax Day/Memorial Day/early June 2016 flood events, where the Houston Metro area (and the rest of the state) experienced a climate similar to the South Asian summer monsoon (in this case, a stalled low-pressure system—usually from an upper-level low from the northeast Pacific Ocean, migrates east, where the northern polar jet stream form the usual omega blocks—originates over the Four Corners region or the Sierra Madre Occidental/Sierra Madre Oriental mountain ranges in northern Mexico).

This is due to the fact that Houston has been the home for the oil and gas industry since its inception in the early 1900s, when there was little environmental regulation.

Harris County, where the bulk of the city has been historically located, is home to 15 Environmental Protection Agency Superfund sites, more than any other area in Texas.

The industries located along the ship channel,[49] coupled with a growing population, have caused a considerable increase in air pollution for the city each year.

Pollution rankings from the EPA and ALA are administered in terms of peak-based standards, focusing strictly on the worst days of the year; on average, ozone levels in Houston are lower than those seen in many other cities of the country, due to dominant winds off the Gulf that ensure clean, marine air.