# Climate of Houston
Houston, Texas, has a humid subtropical climate (Köppen **Cfa**), with hot, humid summers, mild winters, and heavy rainfall distributed through the year, and its weather is strongly shaped by its position near Galveston Bay and the [Gulf of Mexico](https://www.edgepedia.org/gulf-of-mexico).[1](https://dl.tufts.edu/downloads/gt54m3173?filename=n87106077.pdf) • [2](https://journals.ametsoc.org/view/journals/eint/7/4/1087-3562_2003_007_0001_douira_2.0.co_2.xml) Sea-breeze circulations, the urban heat island, landfalling tropical cyclones, and flat, poorly draining clay soils together define the city's climate and its recurring flood and heat hazards.[3](https://doi.org/10.1029/2023WR034466)
| Key fact | Detail |
|---|---|
| Classification | Humid subtropical (Köppen Cfa); subtropical climate with hot, humid summers and mild winters[1](https://dl.tufts.edu/downloads/gt54m3173?filename=n87106077.pdf) • [3](https://doi.org/10.1029/2023WR034466) |
| Temperature normals | At Intercontinental Airport (1991–2020): annual mean 70.5 °F, average high 80.5 °F, average low 60.5 °F; July–August average highs 94.5–94.9 °F[4](https://www.weather.gov/hgx/climate_iah_normals_summary) |
| Precipitation | 51.84 in (1,317 mm) per year at Intercontinental Airport; 55.62 in (1,413 mm) at Hobby Airport, with 107.2 days per year of measurable rain[4](https://www.weather.gov/hgx/climate_iah_normals_summary) • [5](https://www.ncei.noaa.gov/access/services/data/v1?dataTypes=MLY-TMAX-NORMAL%2CMLY-TMIN-NORMAL%2CMLY-TAVG-NORMAL%2CMLY-PRCP-NORMAL%2CMLY-SNOW-NORMAL&dataset=normals-monthly-1991-2020&format=pdf&stations=USW00012918) |
| Records | Record high 109 °F (August 27, 2011 and September 4, 2000); record low 5 °F (January 18, 1930); greatest one-day rainfall 16.07 in (August 27, 2017, during Hurricane Harvey)[4](https://www.weather.gov/hgx/climate_iah_normals_summary) |
| Dominant local circulation | Afternoon sea breeze from the Gulf; its circulation depth averaged 1,500–2,000 m above ground level in summer 2022 observations[6](https://repository.library.noaa.gov/view/noaa/72900/noaa_72900_DS1.pdf) |
| Flood hazard | Hurricane Harvey's peak three-day rainfall of 1,043.4 mm at Baytown had a return period exceeding 9,000 years in the current climate[7](https://doi.org/10.1088/1748-9326/aa9ef2) |
| Projected change | By 2100, sea-breeze intensity weakens 15–20%, near-surface temperature rises up to 3.9 °C, and citywide cooling energy demand nearly doubles[8](https://asu.elsevierpure.com/en/publications/impact-of-urbanization-and-global-warming-on-sea-breeze-heat-stre/) |
## Temperature and rainfall regime
Monthly normals at [George Bush Intercontinental Airport](https://www.edgepedia.org/george-bush-intercontinental-airport), the official observation site for Houston since June 1969, show a modest annual temperature range for a continental location. January averages 53.8 °F (average high 63.8 °F, average low 43.7 °F), while July and August average 85.1 and 85.2 °F with average highs near 95 °F.[4](https://www.weather.gov/hgx/climate_iah_normals_summary) A watershed study in Harris County reports summer (June–August) mean temperature of 28.2 °C and winter (December–February) mean of 11.6 °C, with relative humidity typically between 70% and 75% throughout the year.[3](https://doi.org/10.1029/2023WR034466)
Rain falls in every month. The wettest months at Intercontinental are June (6.00 in) and October (5.46 in), and even the driest month, February, averages 2.97 in.[4](https://www.weather.gov/hgx/climate_iah_normals_summary) At Hobby Airport the 1991–2020 annual precipitation normal is 55.62 in, with 107.2 days per year recording at least 0.01 in and 17.0 days recording an inch or more.[5](https://www.ncei.noaa.gov/access/services/data/v1?dataTypes=MLY-TMAX-NORMAL%2CMLY-TMIN-NORMAL%2CMLY-TAVG-NORMAL%2CMLY-PRCP-NORMAL%2CMLY-SNOW-NORMAL&dataset=normals-monthly-1991-2020&format=pdf&stations=USW00012918) Among 29 large United States cities compared on one dataset, Houston is the wettest, at about 1,939 mm per year.[9](https://www.weatherhack.com/climate/united-states/)
Snow is rare. The record low of 5 °F was set on January 18, 1930, and in the January 2025 Gulf Coast snowstorm, up to 4 inches fell in the Houston area, a community that does not own snowplows.[4](https://www.weather.gov/hgx/climate_iah_normals_summary) • [10](https://apnews.com/article/2e13133da4760f96a72d7173cfe73283)
## Sea breeze and the urban heat island
Because Houston sits near Galveston Bay and the Gulf of Mexico, its weather, particularly in the warm season, is significantly influenced by sea-breeze circulations.[2](https://journals.ametsoc.org/view/journals/eint/7/4/1087-3562_2003_007_0001_douira_2.0.co_2.xml) The sea breeze is a local wind that carries cool marine air inland along a front marked by sharp changes in temperature and humidity; in Houston it typically penetrates as a layer 1,500–2,000 m deep.[6](https://repository.library.noaa.gov/view/noaa/72900/noaa_72900_DS1.pdf)
The urban heat island (UHI), the excess warmth of the city caused when buildings and pavement replace natural land cover, interacts with this circulation in two opposing ways: the elevated land temperature strengthens the land–sea temperature gradient that drives the breeze, while the city's roughness impedes the sea-breeze front.[6](https://repository.library.noaa.gov/view/noaa/72900/noaa_72900_DS1.pdf) Observations from the summer 2022 Convective-cloud Urban Boundary-layer Experiment found high intra-urban variability during sea-breeze days, with near-surface virtual potential temperature varying by almost 10 K across the metropolitan area, coastal urban districts cooler than inland ones, and persistent UHI hot spots even while the breeze was blowing.[6](https://repository.library.noaa.gov/view/noaa/72900/noaa_72900_DS1.pdf) A Climate Central analysis reported that about 73% of Houston-area residents live where the heat island raises temperatures by 8 °F or more.[11](https://www.axios.com/local/houston/2023/08/11/heat-islands-houston)
Modeling of the Houston–Galveston area shows that urbanization favors more shallow cumulus clouds, sustained by enhanced surface heating and low-level moisture convergence; these clouds cool the urban surface and reduce the maximum afternoon heat index, even though urbanization raises the mean heat index.[12](https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2024JD041243) The same modeling found that the city's urban circulation dome can overwhelm the classic sea-breeze signal over the city itself, and that warmer sea surface temperatures strengthen the overnight land breeze while weakening the daytime sea breeze.[12](https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2024JD041243)
## Urban influence on rainfall
Houston is one of the cities where urban-induced rainfall anomalies have been documented. A study of the city's warm-season precipitation found the UHI influence to be of primary significance in causing observed precipitation anomalies, with four proposed mechanisms: an enhanced convergence zone from the interaction of the UHI, sea breeze, and Galveston Bay coastline; added convergence from increased urban surface roughness; destabilization of the boundary layer by the UHI's thermal perturbation; and enhanced aerosols serving as cloud condensation nuclei.[2](https://journals.ametsoc.org/view/journals/eint/7/4/1087-3562_2003_007_0001_douira_2.0.co_2.xml) Radar-based work by Shepherd and colleagues showed elevated rainfall rates downwind of the city, attributed to the interaction of the UHI with the sea breeze.[6](https://repository.library.noaa.gov/view/noaa/72900/noaa_72900_DS1.pdf)
## Tropical cyclones and flooding
The region has a long history of tropical cyclone impacts. The 1900 Galveston hurricane remains the deadliest natural disaster in United States history; Tropical Storm Claudette (1979) produced 43 inches of rain in 24 hours at Alvin; [Tropical Storm Allison (2001)](https://www.edgepedia.org/tropical-storm-allison-2001) devastated Houston and became the costliest tropical storm in United States history; [Hurricane Ike](https://www.edgepedia.org/hurricane-ike) (2008) drove a deadly storm surge along the upper Texas coast; [Hurricane Harvey](https://www.edgepedia.org/hurricane-harvey) (2017) produced unprecedented flooding; and Tropical Storm Imelda (2019) broke several United States rainfall records.[13](https://www.weather.gov/hgx/hurricanes_climatology)
Harvey's rainfall was extraordinary even against this history. The highest observed three-day amount, 1,043.4 mm at Baytown, has a return period of more than 9,000 years at 97.5% one-sided confidence, and return periods exceeded 1,000 years over a large area; more than 80 deaths were attributed to the storm, mostly by drowning.[7](https://doi.org/10.1088/1748-9326/aa9ef2) Flood risk is amplified by the landscape: in the White Oak Bayou watershed, more than 96% of the land is developed and about 60% is impervious, on loamy, high-clay soils with slow drainage, and a shallow water table.[3](https://doi.org/10.1029/2023WR034466) Houston experienced three events comparable to 500-year floods from 2015 to 2017 alone, and Texas leads all states in billion-dollar weather disasters.[14](https://time.com/7301528/climate-scientist-in-texas-floods/)
## Heat, records, and recent trends
The all-time record high of 109 °F was reached twice, on August 27, 2011 and September 4, 2000.[4](https://www.weather.gov/hgx/climate_iah_normals_summary) Extreme heat now arrives earlier in the season; in May 2025, the Texas state climatologist, John Nielsen-Gammon, a professor at [Texas A&M University](https://www.edgepedia.org/texas-a-and-m-university), noted that some Texas cities were forecast to see their longest June strings of triple-digit days on record.[15](https://apnews.com/article/4380e366a65f18f03068d33cc799dcdd)
## Outlook under warming and continued urbanization
A modeling study of the greater Houston area under present and future climate states projects that by 2100, urban expansion and warming together will weaken sea-breeze intensity by approximately 15–20%, reduce its inland penetration by about 20–25 km, and lower the frequency of composite land–sea-breeze days by 10–15% in summer. These changes raise near-surface temperatures by up to 3.9 °C, elevate the heat index by 6–7 °C, and nearly double citywide cooling energy demand, with the greatest heat-stress vulnerability in urban coastal areas, where weakened winds no longer relieve the heat island but still add near-surface humidity.[8](https://asu.elsevierpure.com/en/publications/impact-of-urbanization-and-global-warming-on-sea-breeze-heat-stre/) The same work identifies urban greening, high-reflectance surfaces, and ventilation corridors as mitigation strategies.[8](https://asu.elsevierpure.com/en/publications/impact-of-urbanization-and-global-warming-on-sea-breeze-heat-stre/)
## References
1. [Urbanization of Metropolitan Houston, Texas (2015–2022), Tufts University](https://dl.tufts.edu/downloads/gt54m3173?filename=n87106077.pdf)
2. [Detection of Urban-Induced Rainfall Anomalies in a Major Coastal City, Journal of Environmental Informatics](https://journals.ametsoc.org/view/journals/eint/7/4/1087-3562_2003_007_0001_douira_2.0.co_2.xml)
3. [Pal (2023). An Integrative Framework for Assessment of Urban Flood Response to Changing Climate, Water Resources Research](https://doi.org/10.1029/2023WR034466)
4. [Houston IAH Extremes, Normals, and Annual Summaries, NWS Houston/Galveston](https://www.weather.gov/hgx/climate_iah_normals_summary)
5. [Summary of Monthly Normals, Houston Hobby AP (USW00012918), 1991–2020, NOAA NCEI](https://www.ncei.noaa.gov/access/services/data/v1?dataTypes=MLY-TMAX-NORMAL%2CMLY-TMIN-NORMAL%2CMLY-TAVG-NORMAL%2CMLY-PRCP-NORMAL%2CMLY-SNOW-NORMAL&dataset=normals-monthly-1991-2020&format=pdf&stations=USW00012918)
6. [Ramamurthy, Peña, Liu, and Gonzalez. The Interaction Between Urban Heat Island Intensity and Sea Breeze Effect, NOAA Repository](https://repository.library.noaa.gov/view/noaa/72900/noaa_72900_DS1.pdf)
7. [Attribution of Extreme Rainfall from Hurricane Harvey, August 2017, Environmental Research Letters](https://doi.org/10.1088/1748-9326/aa9ef2)
8. [Tewari et al. (2026). Impact of Urbanization and Global Warming on Sea-Breeze, Heat Stress and Cooling Demand over Greater Houston Area, Atmospheric Research 336:108889](https://asu.elsevierpure.com/en/publications/impact-of-urbanization-and-global-warming-on-sea-breeze-heat-stre/)
9. [United States Climate: 29 Cities Compared, WeatherHack](https://www.weatherhack.com/climate/united-states/)
10. [Once-in-a-Lifetime Southern Snow Eclipses Records That Stood for Decades, AP News](https://apnews.com/article/2e13133da4760f96a72d7173cfe73283)
11. [Examining Greater Houston's Heat Islands, Axios](https://www.axios.com/local/houston/2023/08/11/heat-islands-houston)
12. [Mejia et al. (2024). Role of Clouds in the Urban Heat Island and Extreme Heat: Houston–Galveston Metropolitan Area Case, Journal of Geophysical Research: Atmospheres](https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2024JD041243)
13. [Tropical Cyclone Climatology for SE Texas, NWS Houston/Galveston](https://www.weather.gov/hgx/hurricanes_climatology)
14. [I'm a Climate Scientist in Texas. Here's What the Floods Tell Us, Time](https://time.com/7301528/climate-scientist-in-texas-floods/)
15. [Extreme Heat Will Make It Feel More Like August Than May for Texas, AP News](https://apnews.com/article/4380e366a65f18f03068d33cc799dcdd)
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*Topic: Encyclopedia › Physical world and mathematics › Earth sciences › Climate and weather › Climatology and climates of places › Climate of specific places › Climate of North America, its countries, states, and cities*
*Initially written Sep 17, 2026 · Reviewed: Sep 30, 2026; Oct 15, 2026 · Edited: Sep 30, 2026; Oct 15, 2026 · Last review: Oct 15, 2026*
*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*
License: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license