# Climate Design Data Workflow for Houston, TX

> A source-first workflow for retrieving and recording building-design climate conditions for Houston, TX without mixing climate normals, code zones, and HVAC design percentiles.

- Canonical: https://harth.build/resources/climate-data/climate-design-data-workflow-houston-tx/
- Last updated: 2026-08-31
- Data source: Licensed ASHRAE Climatic Design Information / Standard 169 station data plus the locally adopted energy code. Coordinates 29.7604° N (America/Chicago) are approximate routing references. Figures are illustrative — confirm the representative station and current edition. Climate screening data from the [NASA POWER Climatology API documentation](https://power.larc.nasa.gov/docs/services/api/temporal/climatology/) and [exact point response](https://power.larc.nasa.gov/api/temporal/climatology/point?parameters=T2M%2CT2M_MAX%2CT2M_MIN%2CRH2M%2CPRECTOTCORR%2CWS10M&community=SB&longitude=-95.3698&latitude=29.7604&format=JSON), retrieved 2026-08-31; source period: 20-year Meteorological and Solar Monthly & Annual Climatologies (January 2001 - December 2020). NASA POWER values are gridded screening statistics, not code design conditions or guaranteed local observations.

## Key facts

| Fact | Value |
| --- | --- |
| NASA POWER climatology | 20-year Meteorological and Solar Monthly & Annual Climatologies (January 2001 - December 2020) (API v2.9.7; LST) |
| Annual mean temperature | 20.4 °C (2 m gridded climatology; not a design percentile) |
| Highest monthly maximum | 42.6 °C (August) (monthly climatological statistic) |
| Lowest monthly minimum | -7.8 °C (January) (monthly climatological statistic) |
| Annual relative humidity | 76.8% (2 m gridded climatology) |
| Annual corrected precipitation | 3.41 mm/day (climatological daily rate) |
| Annual wind speed | 3.28 m/s (10 m gridded climatology; not a structural design wind speed) |

## Direct answer

NASA POWER's 2001–2020 climatology at the Houston, TX reference point reports an annual mean 2 m temperature of 20.4 °C and relative humidity of 76.8%. The highest monthly maximum is 42.6 °C in August, while the lowest monthly minimum is -7.8 °C in January; these are screening statistics, not code design temperatures. The point response uses LST and the 20-year Meteorological and Solar Monthly & Annual Climatologies (January 2001 - December 2020); its annual corrected precipitation is 3.41 mm/day and annual 10 m wind speed is 3.28 m/s. Use the monthly series to screen source selection before applying project design conditions. NASA POWER is gridded climatology: verify elevation, microclimate, urban exposure, station or weather-file suitability, current code edition and the authority's required source before design use.

*Content and cited inputs reviewed by [Harth team](https://www.linkedin.com/company/harth-build) · Published 2026-08-17 · Updated 2026-08-31.*

## Which climate inputs control the design?

1. Confirm the project jurisdiction and adopted energy-code edition.
2. Select the authoritative station and record why it applies.
3. Record heating dry-bulb percentiles and cooling dry-bulb with coincident moisture conditions.
4. Keep IP/SI units, edition, observation period and retrieval date with every value.
5. Separate climate-zone envelope requirements from HVAC sizing conditions.

| Field | Required record |
| --- | --- |
| Station | Name, ID, coordinates and elevation |
| Source | Publisher, edition and licensed/public status |
| Heating | 99.6% and 99% dry-bulb |
| Cooling | 0.4%, 1% and 2% dry-bulb plus coincident wet-bulb |
| Moisture | Dew-point or humidity design condition used |
| Code | Adopted edition, amendments and effective date |

## Houston, TX NASA POWER monthly climate screening table

| Month | Mean °C | Monthly max °C | Monthly min °C | RH % | Precipitation mm/day | Wind at 10 m m/s |
| --- | ---: | ---: | ---: | ---: | ---: | ---: |
| January | 10.27 | 26.12 | -7.85 | 80.62 | 2.88 | 3.56 |
| February | 12.50 | 29.79 | -7.16 | 81.37 | 2.46 | 3.71 |
| March | 16.49 | 31.98 | -5.12 | 79.70 | 2.73 | 3.73 |
| April | 20.40 | 36.22 | 1.16 | 77.03 | 2.91 | 3.86 |
| May | 24.64 | 38.58 | 6.29 | 74.45 | 3.83 | 3.58 |
| June | 27.96 | 41.90 | 17.11 | 73.06 | 4.20 | 2.99 |
| July | 28.50 | 40.94 | 18.95 | 74.52 | 3.56 | 2.63 |
| August | 29.03 | 42.65 | 16.62 | 72.02 | 4.03 | 2.57 |
| September | 26.21 | 40.75 | 10.49 | 75.34 | 3.93 | 2.72 |
| October | 21.38 | 35.64 | 2.24 | 75.09 | 4.13 | 3.12 |
| November | 15.91 | 31.11 | -3.21 | 78.18 | 3.14 | 3.35 |
| December | 11.67 | 28.59 | -4.35 | 80.27 | 3.09 | 3.53 |

![Monthly mean, maximum and minimum air temperature for Climate Design Data Workflow for Houston, TX](https://efwwel0vyt9vy5so.public.blob.vercel-storage.com/images/climate-data/climate-design-data-workflow-houston-tx/chart-temperature-1344.webp)

*Monthly air temperature for Climate Design Data Workflow for Houston, TX, plotted from the table above.*

![Mean daily precipitation by month for Climate Design Data Workflow for Houston, TX](https://efwwel0vyt9vy5so.public.blob.vercel-storage.com/images/climate-data/climate-design-data-workflow-houston-tx/chart-precipitation-1344.webp)

*Mean daily precipitation for Climate Design Data Workflow for Houston, TX, plotted from the table above.*

## Month-by-month climate interpretation

- **January:** mean temperature 10.27 °C is 10.18 °C below the annual mean; the monthly max–min span is 33.97 °C. Relative humidity is 80.62% (3.84 points above annual), while corrected precipitation at 2.88 mm/day is 0.53 mm/day drier than the annual daily rate.
- **February:** mean temperature 12.50 °C is 7.95 °C below the annual mean; the monthly max–min span is 36.95 °C. Relative humidity is 81.37% (4.59 points above annual), while corrected precipitation at 2.46 mm/day is 0.95 mm/day drier than the annual daily rate.
- **March:** mean temperature 16.49 °C is 3.96 °C below the annual mean; the monthly max–min span is 37.10 °C. Relative humidity is 79.70% (2.92 points above annual), while corrected precipitation at 2.73 mm/day is 0.68 mm/day drier than the annual daily rate.
- **April:** mean temperature 20.40 °C is 0.05 °C below the annual mean; the monthly max–min span is 35.06 °C. Relative humidity is 77.03% (0.25 points above annual), while corrected precipitation at 2.91 mm/day is 0.50 mm/day drier than the annual daily rate.
- **May:** mean temperature 24.64 °C is 4.19 °C above the annual mean; the monthly max–min span is 32.29 °C. Relative humidity is 74.45% (2.33 points below annual), while corrected precipitation at 3.83 mm/day is 0.42 mm/day wetter than the annual daily rate.
- **June:** mean temperature 27.96 °C is 7.51 °C above the annual mean; the monthly max–min span is 24.79 °C. Relative humidity is 73.06% (3.72 points below annual), while corrected precipitation at 4.20 mm/day is 0.79 mm/day wetter than the annual daily rate.
- **July:** mean temperature 28.50 °C is 8.05 °C above the annual mean; the monthly max–min span is 21.99 °C. Relative humidity is 74.52% (2.26 points below annual), while corrected precipitation at 3.56 mm/day is 0.15 mm/day wetter than the annual daily rate.
- **August:** mean temperature 29.03 °C is 8.58 °C above the annual mean; the monthly max–min span is 26.03 °C. Relative humidity is 72.02% (4.76 points below annual), while corrected precipitation at 4.03 mm/day is 0.62 mm/day wetter than the annual daily rate.
- **September:** mean temperature 26.21 °C is 5.76 °C above the annual mean; the monthly max–min span is 30.26 °C. Relative humidity is 75.34% (1.44 points below annual), while corrected precipitation at 3.93 mm/day is 0.52 mm/day wetter than the annual daily rate.
- **October:** mean temperature 21.38 °C is 0.93 °C above the annual mean; the monthly max–min span is 33.40 °C. Relative humidity is 75.09% (1.69 points below annual), while corrected precipitation at 4.13 mm/day is 0.72 mm/day wetter than the annual daily rate.
- **November:** mean temperature 15.91 °C is 4.54 °C below the annual mean; the monthly max–min span is 34.32 °C. Relative humidity is 78.18% (1.40 points above annual), while corrected precipitation at 3.14 mm/day is 0.27 mm/day drier than the annual daily rate.
- **December:** mean temperature 11.67 °C is 8.78 °C below the annual mean; the monthly max–min span is 32.94 °C. Relative humidity is 80.27% (3.49 points above annual), while corrected precipitation at 3.09 mm/day is 0.32 mm/day drier than the annual daily rate.

Harth retrieved this point climatology from NASA POWER API v2.9.7 for location record us:houston-tx. It is a reproducible screening dataset, not an hourly weather file, forecast, code design condition or substitute for local professional review.

## Where can you explore related guidance?

- [Explore all climate data guidance](https://harth.build/resources/climate-data.md)
- [ASHRAE / IECC Climate Zones Explained (Zones 1–8, A/B/C)](https://harth.build/resources/climate-data/ashrae-climate-zones-explained.md)
- [Heating & Cooling Design Temperatures (99%, 1% / 0.4%)](https://harth.build/resources/climate-data/heating-and-cooling-design-temperatures.md)
- [Climate Design Data Workflow for Austin, TX](https://harth.build/resources/climate-data/climate-design-data-workflow-austin-tx.md)
- [Climate Design Data Workflow for Dallas, TX](https://harth.build/resources/climate-data/climate-design-data-workflow-dallas-tx.md)
- [Sun Path & Solar Angles for Houston, TX](https://harth.build/resources/solar-data/sun-path-and-solar-angles-houston-tx.md)

## Sources and method

Licensed ASHRAE Climatic Design Information / Standard 169 station data plus the locally adopted energy code. Coordinates 29.7604° N (America/Chicago) are approximate routing references. Figures are illustrative — confirm the representative station and current edition. Climate screening data from the [NASA POWER Climatology API documentation](https://power.larc.nasa.gov/docs/services/api/temporal/climatology/) and [exact point response](https://power.larc.nasa.gov/api/temporal/climatology/point?parameters=T2M%2CT2M_MAX%2CT2M_MIN%2CRH2M%2CPRECTOTCORR%2CWS10M&community=SB&longitude=-95.3698&latitude=29.7604&format=JSON), retrieved 2026-08-31; source period: 20-year Meteorological and Solar Monthly & Annual Climatologies (January 2001 - December 2020). NASA POWER values are gridded screening statistics, not code design conditions or guaranteed local observations.

### Source links

- [power.larc.nasa.gov](https://power.larc.nasa.gov/docs/services/api/temporal/climatology/)

- [power.larc.nasa.gov](https://power.larc.nasa.gov/api/temporal/climatology/point?parameters=T2M%2CT2M_MAX%2CT2M_MIN%2CRH2M%2CPRECTOTCORR%2CWS10M&community=SB&longitude=-95.3698&latitude=29.7604&format=JSON)

## Frequently asked questions

### What does NASA POWER climatology show for Houston, TX?

For the Houston, TX reference point, the 2001–2020 NASA POWER climatology reports 20.4 °C annual mean temperature, 76.8% relative humidity and 3.41 mm/day corrected precipitation. The monthly maximum peaks at 42.6 °C in August.

### Can the Houston, TX climatology replace project design temperatures or an hourly weather file?

No. The Houston, TX response is gridded monthly climatology; its lowest monthly minimum of -7.8 °C in January is not a code percentile or observed site extreme. Verify elevation, local exposure, the required weather file or design-condition source and the current adopted code.

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