Climate Design Data Workflow for San Diego, CA

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 · 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.

San Diego, CA NASA POWER monthly climate screening table

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
• ASHRAE / IECC Climate Zones Explained (Zones 1–8, A/B/C)
• Heating & Cooling Design Temperatures (99%, 1% / 0.4%)
• Climate Design Data Workflow for Los Angeles, CA
• Climate Design Data Workflow for Las Vegas, NV
• Sun Path & Solar Angles for San Diego, CA

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 and exact point response, 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

• power.larc.nasa.gov