Climate Design Data: Portsmouth, UK

Direct answer

NASA POWER's 2001–2020 climatology at the Portsmouth reference point reports an annual mean 2 m temperature of 10.8 °C and relative humidity of 85.0%. The highest monthly maximum is 33.7 °C in August, while the lowest monthly minimum is -7.4 °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 2.13 mm/day and annual 10 m wind speed is 5.23 m/s. For climate design data, use the 33.7 °C and -7.4 °C monthly extrema to screen seasonal exposure, then obtain the adopted percentile 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.

Prepared by Harth · Harth transformed the cited NASA POWER climatology into this screening table; project design conditions and local applicability remain unreviewed · Published 2026-08-26 · Updated 2026-08-31.

What must be verified for Portsmouth?

Portsmouth is represented here at approximately 50.7990, -1.0913 for discovery and workflow planning. A project address, parcel, elevation, exposure, authority, and submission date must replace that city-centre reference before design use.

How should climate design data be established?

1. Fix the surveyed site and local time basis.
2. Select an authoritative weather source or a named solar-position algorithm.
3. Record period, percentile or scenario and units.
4. Test sensitivity to elevation, exposure, urban form and horizon.
5. Save the source file, retrieval date and checker in the model record.

What are the limits of this worksheet?

This climate-design-workflow page is a project-starting worksheet, not a design value or approval. The controlling authority and qualified professionals for the Portsmouth site remain authoritative.

Which related searches does this primary location record cover?

This primary route consolidates the location evidence needed for Climate Design Data, Weather File Guide, Overheating Weather Data, Building Climate Checklist. A narrower route should be released only when it adds a materially different official source, calculation, process, threshold or worked example.

Portsmouth NASA POWER monthly climate screening table

Portsmouth ranked monthly climate fingerprint

• Portsmouth mean temperature, highest to lowest: July 17.80 °C, August 17.52 °C, June 15.52 °C, September 15.11 °C, May 12.22 °C, October 11.83 °C, April 9.06 °C, November 8.04 °C, March 6.34 °C, December 5.61 °C, January 4.92 °C, February 4.76 °C.
• Portsmouth monthly maximum, highest to lowest: August 33.69 °C, July 33.43 °C, June 30.10 °C, September 27.78 °C, October 25.96 °C, May 24.50 °C, April 23.56 °C, March 18.59 °C, November 17.40 °C, February 15.34 °C, December 13.82 °C, January 12.94 °C.
• Portsmouth monthly minimum, highest to lowest: July 8.23 °C, August 6.58 °C, June 5.05 °C, September 4.38 °C, May 0.48 °C, October -1.95 °C, April -2.55 °C, November -3.48 °C, March -4.64 °C, December -5.08 °C, February -6.87 °C, January -7.44 °C.
• Portsmouth relative humidity, highest to lowest: December 94.14 %, January 93.58 %, November 91.93 %, February 91.69 %, March 88.44 %, October 86.82 %, April 83.76 %, May 81.02 %, September 79.79 %, June 77.98 %, August 76.33 %, July 74.34 %.
• Portsmouth corrected precipitation, highest to lowest: November 2.91 mm/day, October 2.76 mm/day, December 2.73 mm/day, January 2.54 mm/day, February 2.16 mm/day, August 2.06 mm/day, July 1.87 mm/day, June 1.86 mm/day, March 1.84 mm/day, May 1.74 mm/day, April 1.59 mm/day, September 1.53 mm/day.
• Portsmouth 10 m wind speed, highest to lowest: January 6.05 m/s, February 5.92 m/s, December 5.76 m/s, March 5.53 m/s, November 5.50 m/s, October 5.47 m/s, September 4.90 m/s, May 4.82 m/s, August 4.76 m/s, April 4.74 m/s, July 4.71 m/s, June 4.58 m/s.

Portsmouth month-to-month screening ledger

• Portsmouth January: mean 4.92 °C, change from December -0.69 °C; max–min span 20.38 °C; humidity 93.58%, change -0.56 points; precipitation 2.54 mm/day; wind 6.05 m/s.
• Portsmouth February: mean 4.76 °C, change from January -0.16 °C; max–min span 22.21 °C; humidity 91.69%, change -1.89 points; precipitation 2.16 mm/day; wind 5.92 m/s.
• Portsmouth March: mean 6.34 °C, change from February +1.58 °C; max–min span 23.23 °C; humidity 88.44%, change -3.25 points; precipitation 1.84 mm/day; wind 5.53 m/s.
• Portsmouth April: mean 9.06 °C, change from March +2.72 °C; max–min span 26.11 °C; humidity 83.76%, change -4.68 points; precipitation 1.59 mm/day; wind 4.74 m/s.
• Portsmouth May: mean 12.22 °C, change from April +3.16 °C; max–min span 24.02 °C; humidity 81.02%, change -2.74 points; precipitation 1.74 mm/day; wind 4.82 m/s.
• Portsmouth June: mean 15.52 °C, change from May +3.30 °C; max–min span 25.05 °C; humidity 77.98%, change -3.04 points; precipitation 1.86 mm/day; wind 4.58 m/s.
• Portsmouth July: mean 17.80 °C, change from June +2.28 °C; max–min span 25.20 °C; humidity 74.34%, change -3.64 points; precipitation 1.87 mm/day; wind 4.71 m/s.
• Portsmouth August: mean 17.52 °C, change from July -0.28 °C; max–min span 27.11 °C; humidity 76.33%, change +1.99 points; precipitation 2.06 mm/day; wind 4.76 m/s.
• Portsmouth September: mean 15.11 °C, change from August -2.41 °C; max–min span 23.40 °C; humidity 79.79%, change +3.46 points; precipitation 1.53 mm/day; wind 4.90 m/s.
• Portsmouth October: mean 11.83 °C, change from September -3.28 °C; max–min span 27.91 °C; humidity 86.82%, change +7.03 points; precipitation 2.76 mm/day; wind 5.47 m/s.
• Portsmouth November: mean 8.04 °C, change from October -3.79 °C; max–min span 20.88 °C; humidity 91.93%, change +5.11 points; precipitation 2.91 mm/day; wind 5.50 m/s.
• Portsmouth December: mean 5.61 °C, change from November -2.43 °C; max–min span 18.90 °C; humidity 94.14%, change +2.21 points; precipitation 2.73 mm/day; wind 5.76 m/s.

Harth retrieved this point climatology from NASA POWER API v2.9.7 for location record 2639996. The ranked fingerprint and transition ledger preserve Portsmouth's monthly order and successive changes for source comparison. This 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
• Climate Design Data: Southampton, UK
• Climate Design Data: Reading, UK
• Climate Design Data: Brighton, UK
• Climate Design Data: Swindon, UK
• All climate & energy design data guidance for United Kingdom
• Sun Path: Portsmouth, UK

Sources and method

Location data from the GeoNames GB dump (CC BY 4.0, snapshot 2026-08-31, GeoNames ID 2639996). Regulatory starting point: UK and devolved building-control authorities. Figures are illustrative — verify against the current locally adopted edition for the site. 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

• download.geonames.org

• gov.uk

• power.larc.nasa.gov

• power.larc.nasa.gov