# Climate Design Data Workflow for Dallas, TX

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

- Canonical: https://harth.build/resources/climate-data/climate-design-data-workflow-dallas-tx/
- Last updated: 2026-08-31
- Data source: Licensed ASHRAE Climatic Design Information / Standard 169 station data plus the locally adopted energy code. Coordinates 32.7767° 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=-96.797&latitude=32.7767&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 | 18.6 °C (2 m gridded climatology; not a design percentile) |
| Highest monthly maximum | 45.3 °C (July) (monthly climatological statistic) |
| Lowest monthly minimum | -11.2 °C (January) (monthly climatological statistic) |
| Annual relative humidity | 68.7% (2 m gridded climatology) |
| Annual corrected precipitation | 2.53 mm/day (climatological daily rate) |
| Annual wind speed | 4.46 m/s (10 m gridded climatology; not a structural design wind speed) |

## Direct answer

NASA POWER's 2001–2020 climatology at the Dallas, TX reference point reports an annual mean 2 m temperature of 18.6 °C and relative humidity of 68.7%. The highest monthly maximum is 45.3 °C in July, while the lowest monthly minimum is -11.2 °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 2.53 mm/day and annual 10 m wind speed is 4.46 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 |

## Dallas, 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 | 6.42 | 27.73 | -11.18 | 73.22 | 1.87 | 4.69 |
| February | 8.57 | 30.81 | -9.88 | 74.33 | 2.36 | 4.98 |
| March | 13.65 | 30.68 | -8.68 | 73.31 | 2.84 | 5.12 |
| April | 18.26 | 37.44 | -0.74 | 71.59 | 2.75 | 5.27 |
| May | 22.86 | 39.21 | 3.97 | 72.46 | 3.75 | 4.70 |
| June | 27.54 | 42.19 | 14.30 | 67.41 | 3.21 | 4.21 |
| July | 29.83 | 45.33 | 17.67 | 60.57 | 1.79 | 3.79 |
| August | 30.06 | 44.86 | 15.77 | 58.25 | 2.01 | 3.59 |
| September | 25.78 | 42.30 | 10.15 | 63.39 | 2.56 | 3.67 |
| October | 19.25 | 37.02 | -2.51 | 66.24 | 3.29 | 4.32 |
| November | 12.93 | 32.71 | -6.34 | 70.80 | 1.91 | 4.67 |
| December | 7.61 | 28.94 | -9.99 | 72.71 | 1.96 | 4.59 |

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

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

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

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

## Month-by-month climate interpretation

- **January:** mean temperature 6.42 °C is 12.19 °C below the annual mean; the monthly max–min span is 38.91 °C. Relative humidity is 73.22% (4.57 points above annual), while corrected precipitation at 1.87 mm/day is 0.66 mm/day drier than the annual daily rate.
- **February:** mean temperature 8.57 °C is 10.04 °C below the annual mean; the monthly max–min span is 40.69 °C. Relative humidity is 74.33% (5.68 points above annual), while corrected precipitation at 2.36 mm/day is 0.17 mm/day drier than the annual daily rate.
- **March:** mean temperature 13.65 °C is 4.96 °C below the annual mean; the monthly max–min span is 39.36 °C. Relative humidity is 73.31% (4.66 points above annual), while corrected precipitation at 2.84 mm/day is 0.31 mm/day wetter than the annual daily rate.
- **April:** mean temperature 18.26 °C is 0.35 °C below the annual mean; the monthly max–min span is 38.18 °C. Relative humidity is 71.59% (2.94 points above annual), while corrected precipitation at 2.75 mm/day is 0.22 mm/day wetter than the annual daily rate.
- **May:** mean temperature 22.86 °C is 4.25 °C above the annual mean; the monthly max–min span is 35.24 °C. Relative humidity is 72.46% (3.81 points above annual), while corrected precipitation at 3.75 mm/day is 1.22 mm/day wetter than the annual daily rate.
- **June:** mean temperature 27.54 °C is 8.93 °C above the annual mean; the monthly max–min span is 27.89 °C. Relative humidity is 67.41% (1.24 points below annual), while corrected precipitation at 3.21 mm/day is 0.68 mm/day wetter than the annual daily rate.
- **July:** mean temperature 29.83 °C is 11.22 °C above the annual mean; the monthly max–min span is 27.66 °C. Relative humidity is 60.57% (8.08 points below annual), while corrected precipitation at 1.79 mm/day is 0.74 mm/day drier than the annual daily rate.
- **August:** mean temperature 30.06 °C is 11.45 °C above the annual mean; the monthly max–min span is 29.09 °C. Relative humidity is 58.25% (10.40 points below annual), while corrected precipitation at 2.01 mm/day is 0.52 mm/day drier than the annual daily rate.
- **September:** mean temperature 25.78 °C is 7.17 °C above the annual mean; the monthly max–min span is 32.15 °C. Relative humidity is 63.39% (5.26 points below annual), while corrected precipitation at 2.56 mm/day is 0.03 mm/day wetter than the annual daily rate.
- **October:** mean temperature 19.25 °C is 0.64 °C above the annual mean; the monthly max–min span is 39.53 °C. Relative humidity is 66.24% (2.41 points below annual), while corrected precipitation at 3.29 mm/day is 0.76 mm/day wetter than the annual daily rate.
- **November:** mean temperature 12.93 °C is 5.68 °C below the annual mean; the monthly max–min span is 39.05 °C. Relative humidity is 70.80% (2.15 points above annual), while corrected precipitation at 1.91 mm/day is 0.62 mm/day drier than the annual daily rate.
- **December:** mean temperature 7.61 °C is 11.00 °C below the annual mean; the monthly max–min span is 38.93 °C. Relative humidity is 72.71% (4.06 points above annual), while corrected precipitation at 1.96 mm/day is 0.57 mm/day drier than the annual daily rate.

Harth retrieved this point climatology from NASA POWER API v2.9.7 for location record us:dallas-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 Houston, TX](https://harth.build/resources/climate-data/climate-design-data-workflow-houston-tx.md)
- [Sun Path & Solar Angles for Dallas, TX](https://harth.build/resources/solar-data/sun-path-and-solar-angles-dallas-tx.md)

## Sources and method

Licensed ASHRAE Climatic Design Information / Standard 169 station data plus the locally adopted energy code. Coordinates 32.7767° 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=-96.797&latitude=32.7767&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=-96.797&latitude=32.7767&format=JSON)

## Frequently asked questions

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

For the Dallas, TX reference point, the 2001–2020 NASA POWER climatology reports 18.6 °C annual mean temperature, 68.7% relative humidity and 2.53 mm/day corrected precipitation. The monthly maximum peaks at 45.3 °C in July.

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

No. The Dallas, TX response is gridded monthly climatology; its lowest monthly minimum of -11.2 °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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