# Climate Design Data Workflow for Boston, MA

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

- Canonical: https://harth.build/resources/climate-data/climate-design-data-workflow-boston-ma/
- Last updated: 2026-08-31
- Data source: Licensed ASHRAE Climatic Design Information / Standard 169 station data plus the locally adopted energy code. Coordinates 42.3601° N (America/New_York) 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=-71.0589&latitude=42.3601&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 | 9.6 °C (2 m gridded climatology; not a design percentile) |
| Highest monthly maximum | 38.0 °C (August) (monthly climatological statistic) |
| Lowest monthly minimum | -25.9 °C (February) (monthly climatological statistic) |
| Annual relative humidity | 80.3% (2 m gridded climatology) |
| Annual corrected precipitation | 3.31 mm/day (climatological daily rate) |
| Annual wind speed | 2.55 m/s (10 m gridded climatology; not a structural design wind speed) |

## Direct answer

NASA POWER's 2001–2020 climatology at the Boston, MA reference point reports an annual mean 2 m temperature of 9.6 °C and relative humidity of 80.3%. The highest monthly maximum is 38.0 °C in August, while the lowest monthly minimum is -25.9 °C in February; 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 3.31 mm/day and annual 10 m wind speed is 2.55 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 |

## Boston, MA 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 | -3.54 | 17.95 | -24.32 | 88.16 | 2.59 | 3.23 |
| February | -2.63 | 18.34 | -25.92 | 86.58 | 3.06 | 3.36 |
| March | 1.30 | 23.91 | -19.46 | 82.47 | 3.55 | 3.24 |
| April | 7.41 | 30.05 | -7.95 | 79.30 | 3.55 | 2.77 |
| May | 13.43 | 31.61 | -0.62 | 78.94 | 3.06 | 2.26 |
| June | 18.57 | 33.78 | 4.65 | 79.25 | 3.77 | 1.95 |
| July | 22.43 | 36.35 | 10.13 | 75.33 | 3.03 | 1.84 |
| August | 22.07 | 38.01 | 10.18 | 73.13 | 3.01 | 1.85 |
| September | 18.17 | 35.85 | 4.93 | 74.50 | 3.06 | 2.06 |
| October | 11.47 | 30.09 | -5.81 | 78.62 | 3.96 | 2.48 |
| November | 5.31 | 22.34 | -12.38 | 81.57 | 3.26 | 2.65 |
| December | 0.02 | 19.62 | -19.88 | 86.21 | 3.73 | 2.94 |

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

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

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

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

## Month-by-month climate interpretation

- **January:** mean temperature -3.54 °C is 13.10 °C below the annual mean; the monthly max–min span is 42.27 °C. Relative humidity is 88.16% (7.85 points above annual), while corrected precipitation at 2.59 mm/day is 0.72 mm/day drier than the annual daily rate.
- **February:** mean temperature -2.63 °C is 12.19 °C below the annual mean; the monthly max–min span is 44.26 °C. Relative humidity is 86.58% (6.27 points above annual), while corrected precipitation at 3.06 mm/day is 0.25 mm/day drier than the annual daily rate.
- **March:** mean temperature 1.30 °C is 8.26 °C below the annual mean; the monthly max–min span is 43.37 °C. Relative humidity is 82.47% (2.16 points above annual), while corrected precipitation at 3.55 mm/day is 0.24 mm/day wetter than the annual daily rate.
- **April:** mean temperature 7.41 °C is 2.15 °C below the annual mean; the monthly max–min span is 38.00 °C. Relative humidity is 79.30% (1.01 points below annual), while corrected precipitation at 3.55 mm/day is 0.24 mm/day wetter than the annual daily rate.
- **May:** mean temperature 13.43 °C is 3.87 °C above the annual mean; the monthly max–min span is 32.23 °C. Relative humidity is 78.94% (1.37 points below annual), while corrected precipitation at 3.06 mm/day is 0.25 mm/day drier than the annual daily rate.
- **June:** mean temperature 18.57 °C is 9.01 °C above the annual mean; the monthly max–min span is 29.13 °C. Relative humidity is 79.25% (1.06 points below annual), while corrected precipitation at 3.77 mm/day is 0.46 mm/day wetter than the annual daily rate.
- **July:** mean temperature 22.43 °C is 12.87 °C above the annual mean; the monthly max–min span is 26.22 °C. Relative humidity is 75.33% (4.98 points below annual), while corrected precipitation at 3.03 mm/day is 0.28 mm/day drier than the annual daily rate.
- **August:** mean temperature 22.07 °C is 12.51 °C above the annual mean; the monthly max–min span is 27.83 °C. Relative humidity is 73.13% (7.18 points below annual), while corrected precipitation at 3.01 mm/day is 0.30 mm/day drier than the annual daily rate.
- **September:** mean temperature 18.17 °C is 8.61 °C above the annual mean; the monthly max–min span is 30.92 °C. Relative humidity is 74.50% (5.81 points below annual), while corrected precipitation at 3.06 mm/day is 0.25 mm/day drier than the annual daily rate.
- **October:** mean temperature 11.47 °C is 1.91 °C above the annual mean; the monthly max–min span is 35.90 °C. Relative humidity is 78.62% (1.69 points below annual), while corrected precipitation at 3.96 mm/day is 0.65 mm/day wetter than the annual daily rate.
- **November:** mean temperature 5.31 °C is 4.25 °C below the annual mean; the monthly max–min span is 34.72 °C. Relative humidity is 81.57% (1.26 points above annual), while corrected precipitation at 3.26 mm/day is 0.05 mm/day drier than the annual daily rate.
- **December:** mean temperature 0.02 °C is 9.54 °C below the annual mean; the monthly max–min span is 39.50 °C. Relative humidity is 86.21% (5.90 points above annual), while corrected precipitation at 3.73 mm/day is 0.42 mm/day wetter than the annual daily rate.

Harth retrieved this point climatology from NASA POWER API v2.9.7 for location record us:boston-ma. 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 New York, NY](https://harth.build/resources/climate-data/climate-design-data-workflow-new-york-ny.md)
- [Climate Design Data Workflow for Washington, DC](https://harth.build/resources/climate-data/climate-design-data-workflow-washington-dc.md)
- [Sun Path & Solar Angles for Boston, MA](https://harth.build/resources/solar-data/sun-path-and-solar-angles-boston-ma.md)

## Sources and method

Licensed ASHRAE Climatic Design Information / Standard 169 station data plus the locally adopted energy code. Coordinates 42.3601° N (America/New_York) 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=-71.0589&latitude=42.3601&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=-71.0589&latitude=42.3601&format=JSON)

## Frequently asked questions

### What does NASA POWER climatology show for Boston, MA?

For the Boston, MA reference point, the 2001–2020 NASA POWER climatology reports 9.6 °C annual mean temperature, 80.3% relative humidity and 3.31 mm/day corrected precipitation. The monthly maximum peaks at 38.0 °C in August.

### Can the Boston, MA climatology replace project design temperatures or an hourly weather file?

No. The Boston, MA response is gridded monthly climatology; its lowest monthly minimum of -25.9 °C in February 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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