Climate Design Data: Welkom, South Africa

Direct answer

NASA POWER's 2001–2020 climatology at the Welkom reference point reports an annual mean 2 m temperature of 17.6 °C and relative humidity of 49.7%. The highest monthly maximum is 41.6 °C in January, while the lowest monthly minimum is -5.6 °C in August; 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 1.44 mm/day and annual 10 m wind speed is 3.56 m/s. For climate design data, use the 41.6 °C and -5.6 °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 Welkom?

Welkom is represented here at approximately -27.9774, 26.7351 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 Welkom 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.

Welkom NASA POWER monthly climate screening table

Month-by-month climate interpretation

• January: mean temperature 23.96 °C is 6.41 °C above the annual mean; the monthly max–min span is 34.04 °C. Relative humidity is 53.35% (3.67 points above annual), while corrected precipitation at 2.81 mm/day is 1.37 mm/day wetter than the annual daily rate.
• February: mean temperature 23.10 °C is 5.55 °C above the annual mean; the monthly max–min span is 30.60 °C. Relative humidity is 55.77% (6.09 points above annual), while corrected precipitation at 2.61 mm/day is 1.17 mm/day wetter than the annual daily rate.
• March: mean temperature 21.06 °C is 3.51 °C above the annual mean; the monthly max–min span is 31.62 °C. Relative humidity is 56.15% (6.47 points above annual), while corrected precipitation at 2.33 mm/day is 0.89 mm/day wetter than the annual daily rate.
• April: mean temperature 16.94 °C is 0.61 °C below the annual mean; the monthly max–min span is 33.24 °C. Relative humidity is 58.07% (8.39 points above annual), while corrected precipitation at 1.38 mm/day is 0.06 mm/day drier than the annual daily rate.
• May: mean temperature 13.16 °C is 4.39 °C below the annual mean; the monthly max–min span is 33.70 °C. Relative humidity is 52.77% (3.09 points above annual), while corrected precipitation at 0.39 mm/day is 1.05 mm/day drier than the annual daily rate.
• June: mean temperature 9.31 °C is 8.24 °C below the annual mean; the monthly max–min span is 29.95 °C. Relative humidity is 54.80% (5.12 points above annual), while corrected precipitation at 0.39 mm/day is 1.05 mm/day drier than the annual daily rate.
• July: mean temperature 9.08 °C is 8.47 °C below the annual mean; the monthly max–min span is 30.39 °C. Relative humidity is 50.13% (0.45 points above annual), while corrected precipitation at 0.14 mm/day is 1.30 mm/day drier than the annual daily rate.
• August: mean temperature 12.08 °C is 5.47 °C below the annual mean; the monthly max–min span is 36.53 °C. Relative humidity is 43.31% (6.37 points below annual), while corrected precipitation at 0.31 mm/day is 1.13 mm/day drier than the annual daily rate.
• September: mean temperature 16.79 °C is 0.76 °C below the annual mean; the monthly max–min span is 37.11 °C. Relative humidity is 35.74% (13.94 points below annual), while corrected precipitation at 0.37 mm/day is 1.07 mm/day drier than the annual daily rate.
• October: mean temperature 20.22 °C is 2.67 °C above the annual mean; the monthly max–min span is 35.13 °C. Relative humidity is 40.67% (9.01 points below annual), while corrected precipitation at 1.32 mm/day is 0.12 mm/day drier than the annual daily rate.
• November: mean temperature 21.79 °C is 4.24 °C above the annual mean; the monthly max–min span is 34.54 °C. Relative humidity is 45.62% (4.06 points below annual), while corrected precipitation at 2.41 mm/day is 0.97 mm/day wetter than the annual daily rate.
• December: mean temperature 23.39 °C is 5.84 °C above the annual mean; the monthly max–min span is 33.19 °C. Relative humidity is 50.22% (0.54 points above annual), while corrected precipitation at 2.87 mm/day is 1.43 mm/day wetter than the annual daily rate.

Harth retrieved this point climatology from NASA POWER API v2.9.7 for location record 940909. 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
• Climate Design Data: Klerksdorp, South Africa
• Climate Design Data: Bloemfontein, South Africa
• Climate Design Data: Botshabelo, South Africa
• Climate Design Data: Potchefstroom, South Africa

Sources and method

Location data from the GeoNames ZA dump (CC BY 4.0, snapshot 2026-08-31, GeoNames ID 940909). Regulatory starting point: South African Bureau of Standards and the local authority. 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

• sabs.co.za

• power.larc.nasa.gov

• power.larc.nasa.gov