# Climate Design Data Workflow for San Diego, CA

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

- Canonical: https://harth.build/resources/climate-data/climate-design-data-workflow-san-diego-ca/
- Last updated: 2026-08-31
- Data source: Licensed ASHRAE Climatic Design Information / Standard 169 station data plus the locally adopted energy code. Coordinates 32.7157° N (America/Los_Angeles) 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=-117.1611&latitude=32.7157&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 | 17.0 °C (2 m gridded climatology; not a design percentile) |
| Highest monthly maximum | 40.9 °C (July) (monthly climatological statistic) |
| Lowest monthly minimum | -0.3 °C (January) (monthly climatological statistic) |
| Annual relative humidity | 62.6% (2 m gridded climatology) |
| Annual corrected precipitation | 0.73 mm/day (climatological daily rate) |
| Annual wind speed | 3.07 m/s (10 m gridded climatology; not a structural design wind speed) |

## Direct answer

NASA POWER's 2001–2020 climatology at the San Diego, CA reference point reports an annual mean 2 m temperature of 17.0 °C and relative humidity of 62.6%. The highest monthly maximum is 40.9 °C in July, while the lowest monthly minimum is -0.3 °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 0.73 mm/day and annual 10 m wind speed is 3.07 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 |

## San Diego, CA 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 | 12.36 | 27.58 | -0.31 | 63.53 | 1.32 | 3.46 |
| February | 12.47 | 28.95 | 1.84 | 66.39 | 1.96 | 3.48 |
| March | 13.81 | 30.09 | 4.46 | 67.63 | 0.94 | 3.18 |
| April | 14.84 | 33.10 | 5.04 | 67.66 | 0.58 | 3.38 |
| May | 16.64 | 35.34 | 7.49 | 67.55 | 0.24 | 3.23 |
| June | 19.09 | 38.78 | 8.43 | 63.48 | 0.46 | 2.86 |
| July | 22.50 | 40.93 | 11.14 | 58.16 | 0.13 | 2.68 |
| August | 23.15 | 37.81 | 10.83 | 56.63 | 0.13 | 2.56 |
| September | 22.45 | 39.12 | 11.41 | 56.81 | 0.19 | 2.55 |
| October | 19.15 | 36.92 | 7.16 | 59.64 | 0.47 | 2.78 |
| November | 15.60 | 31.55 | 2.56 | 59.77 | 0.83 | 3.12 |
| December | 12.16 | 27.17 | 1.75 | 64.28 | 1.65 | 3.54 |

![Monthly mean, maximum and minimum air temperature for Climate Design Data Workflow for San Diego, CA](https://efwwel0vyt9vy5so.public.blob.vercel-storage.com/images/climate-data/climate-design-data-workflow-san-diego-ca/chart-temperature-1344.webp)

*Monthly air temperature for Climate Design Data Workflow for San Diego, CA, plotted from the table above.*

![Mean daily precipitation by month for Climate Design Data Workflow for San Diego, CA](https://efwwel0vyt9vy5so.public.blob.vercel-storage.com/images/climate-data/climate-design-data-workflow-san-diego-ca/chart-precipitation-1344.webp)

*Mean daily precipitation for Climate Design Data Workflow for San Diego, CA, plotted from the table above.*

## Month-by-month climate interpretation

- **January:** mean temperature 12.36 °C is 4.68 °C below the annual mean; the monthly max–min span is 27.89 °C. Relative humidity is 63.53% (0.93 points above annual), while corrected precipitation at 1.32 mm/day is 0.59 mm/day wetter than the annual daily rate.
- **February:** mean temperature 12.47 °C is 4.57 °C below the annual mean; the monthly max–min span is 27.11 °C. Relative humidity is 66.39% (3.79 points above annual), while corrected precipitation at 1.96 mm/day is 1.23 mm/day wetter than the annual daily rate.
- **March:** mean temperature 13.81 °C is 3.23 °C below the annual mean; the monthly max–min span is 25.63 °C. Relative humidity is 67.63% (5.03 points above annual), while corrected precipitation at 0.94 mm/day is 0.21 mm/day wetter than the annual daily rate.
- **April:** mean temperature 14.84 °C is 2.20 °C below the annual mean; the monthly max–min span is 28.06 °C. Relative humidity is 67.66% (5.06 points above annual), while corrected precipitation at 0.58 mm/day is 0.15 mm/day drier than the annual daily rate.
- **May:** mean temperature 16.64 °C is 0.40 °C below the annual mean; the monthly max–min span is 27.85 °C. Relative humidity is 67.55% (4.95 points above annual), while corrected precipitation at 0.24 mm/day is 0.49 mm/day drier than the annual daily rate.
- **June:** mean temperature 19.09 °C is 2.05 °C above the annual mean; the monthly max–min span is 30.35 °C. Relative humidity is 63.48% (0.88 points above annual), while corrected precipitation at 0.46 mm/day is 0.27 mm/day drier than the annual daily rate.
- **July:** mean temperature 22.50 °C is 5.46 °C above the annual mean; the monthly max–min span is 29.79 °C. Relative humidity is 58.16% (4.44 points below annual), while corrected precipitation at 0.13 mm/day is 0.60 mm/day drier than the annual daily rate.
- **August:** mean temperature 23.15 °C is 6.11 °C above the annual mean; the monthly max–min span is 26.98 °C. Relative humidity is 56.63% (5.97 points below annual), while corrected precipitation at 0.13 mm/day is 0.60 mm/day drier than the annual daily rate.
- **September:** mean temperature 22.45 °C is 5.41 °C above the annual mean; the monthly max–min span is 27.71 °C. Relative humidity is 56.81% (5.79 points below annual), while corrected precipitation at 0.19 mm/day is 0.54 mm/day drier than the annual daily rate.
- **October:** mean temperature 19.15 °C is 2.11 °C above the annual mean; the monthly max–min span is 29.76 °C. Relative humidity is 59.64% (2.96 points below annual), while corrected precipitation at 0.47 mm/day is 0.26 mm/day drier than the annual daily rate.
- **November:** mean temperature 15.60 °C is 1.44 °C below the annual mean; the monthly max–min span is 28.99 °C. Relative humidity is 59.77% (2.83 points below annual), while corrected precipitation at 0.83 mm/day is 0.10 mm/day wetter than the annual daily rate.
- **December:** mean temperature 12.16 °C is 4.88 °C below the annual mean; the monthly max–min span is 25.42 °C. Relative humidity is 64.28% (1.68 points above annual), while corrected precipitation at 1.65 mm/day is 0.92 mm/day wetter than the annual daily rate.

Harth retrieved this point climatology from NASA POWER API v2.9.7 for location record us:san-diego-ca. 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 Los Angeles, CA](https://harth.build/resources/climate-data/climate-design-data-workflow-los-angeles-ca.md)
- [Climate Design Data Workflow for Las Vegas, NV](https://harth.build/resources/climate-data/climate-design-data-workflow-las-vegas-nv.md)
- [Sun Path & Solar Angles for San Diego, CA](https://harth.build/resources/solar-data/sun-path-and-solar-angles-san-diego-ca.md)

## Sources and method

Licensed ASHRAE Climatic Design Information / Standard 169 station data plus the locally adopted energy code. Coordinates 32.7157° N (America/Los_Angeles) 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=-117.1611&latitude=32.7157&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=-117.1611&latitude=32.7157&format=JSON)

## Frequently asked questions

### What does NASA POWER climatology show for San Diego, CA?

For the San Diego, CA reference point, the 2001–2020 NASA POWER climatology reports 17.0 °C annual mean temperature, 62.6% relative humidity and 0.73 mm/day corrected precipitation. The monthly maximum peaks at 40.9 °C in July.

### Can the San Diego, CA climatology replace project design temperatures or an hourly weather file?

No. The San Diego, CA response is gridded monthly climatology; its lowest monthly minimum of -0.3 °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.

---

- Continue in Harth (open this topic in the Harth agent): https://app.harth.build/?context=%2Fresources%2Fclimate-data%2Fclimate-design-data-workflow-san-diego-ca%2F
- View this page in a browser: https://harth.build/resources/climate-data/climate-design-data-workflow-san-diego-ca/
- All resources for agents: https://harth.build/llms.txt