Solar & Daylight Data

Updated 2026-08-31

Sun Path: Swindon, UK

How to research sun path for a specific site in Swindon — the controlling authority, source documents, and checks to run before you rely on a number.

Last updated August 31, 2026 · Location data from the [GeoNames GB dump](https://download.geonames.org/export/dump/GB.zip) (CC BY 4.0, snapshot 2026-08-31, GeoNames ID 2636389). Regulatory starting point: [UK and devolved building-control authorities](https://www.gov.uk/government/collections/approved-documents). Figures are illustrative — verify against the current locally adopted edition for the site. Solar-method context: [NOAA Solar Calculation Details](https://gml.noaa.gov/grad/solcalc/calcdetails.html); the Harth monthly table uses a simpler declination and geometric-daylight approximation whose stated limitations must be retained.

Direct answer

For Swindon at 51.5580, -1.7812, the declination-only solar-noon altitude is approximately 61.9° at the June solstice, 38.4° at an equinox and 15.0° at the December solstice. Refine these geometry checks with the project date, civil time, facade azimuth, terrain and local horizon. The reproducible location record is GeoNames ID 2636389 in administrative area ENG, at 51.5580, -1.7812; replace it with the surveyed parcel point before relying on the result. As a transparent geometry check, declination-only solar-noon altitude is about 61.9° at the June solstice, 38.4° at an equinox and 15.0° at the December solstice. Representative 21st-day geometry ranges from about 7.6 hours in December to 16.4 hours in June; this excludes atmospheric refraction, terrain and obstruction effects. The cited national authority is a discovery starting point; current local documents and a named qualified reviewer control project use of this sun path record.

Prepared by Harth · Prepared from the cited location and country sources; local project inputs remain unreviewed · Published 2026-08-26 · Updated 2026-08-31.

What must be verified for Swindon?

Swindon is represented here at approximately 51.5580, -1.7812 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 sun path 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.
InputProject-specific evidenceQA question
Sitesurveyed coordinates, elevation and horizonDoes the point represent the building?
Weather/solar methodnamed dataset, algorithm, period and time basisAre station, time zone and units explicit?
Design scenariocurrent and future scenario agreed by the teamIs an average being mistaken for an extreme?
Complianceadopted local document and editionWas applicability confirmed with the authority?

What are the limits of this worksheet?

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

This primary route consolidates the location evidence needed for Sun Path, Solar Altitude & Azimuth, Solar Shading Design, Daylight & Orientation. A narrower route should be released only when it adds a materially different official source, calculation, process, threshold or worked example.

Swindon monthly solar geometry check for sun path

Representative dateDeclinationSolar-noon altitudeGeometric daylightNoon shadow / height
21 January-20.14°18.30°8.331 h3.023
21 February-11.23°27.22°10.069 h1.944
21 March-0.40°38.04°11.932 h1.278
21 April+11.58°50.02°13.994 h0.838
21 May+20.14°58.58°15.669 h0.611
21 June+23.45°61.89°16.417 h0.534
21 July+20.44°58.88°15.734 h0.604
21 August+11.75°50.20°14.026 h0.833
21 September-0.20°38.24°11.966 h1.269
21 October-11.75°26.69°9.974 h1.989
21 November-20.44°18.00°8.266 h3.078
21 December-23.45°14.99°7.583 h3.734

Swindon solar-geometry fingerprint at 51.5580, -1.7812

  • Swindon, 21 January: declination -20.14°, noon altitude 18.30°, zenith 71.70°, geometric daylight 8.331 hours, and vertical-object noon shadow ratio 3.023.
  • Swindon, 21 February: declination -11.23°, noon altitude 27.22°, zenith 62.78°, geometric daylight 10.069 hours, and vertical-object noon shadow ratio 1.944.
  • Swindon, 21 March: declination -0.40°, noon altitude 38.04°, zenith 51.96°, geometric daylight 11.932 hours, and vertical-object noon shadow ratio 1.278.
  • Swindon, 21 April: declination +11.58°, noon altitude 50.02°, zenith 39.98°, geometric daylight 13.994 hours, and vertical-object noon shadow ratio 0.838.
  • Swindon, 21 May: declination +20.14°, noon altitude 58.58°, zenith 31.42°, geometric daylight 15.669 hours, and vertical-object noon shadow ratio 0.611.
  • Swindon, 21 June: declination +23.45°, noon altitude 61.89°, zenith 28.11°, geometric daylight 16.417 hours, and vertical-object noon shadow ratio 0.534.
  • Swindon, 21 July: declination +20.44°, noon altitude 58.88°, zenith 31.12°, geometric daylight 15.734 hours, and vertical-object noon shadow ratio 0.604.
  • Swindon, 21 August: declination +11.75°, noon altitude 50.20°, zenith 39.80°, geometric daylight 14.026 hours, and vertical-object noon shadow ratio 0.833.
  • Swindon, 21 September: declination -0.20°, noon altitude 38.24°, zenith 51.76°, geometric daylight 11.966 hours, and vertical-object noon shadow ratio 1.269.
  • Swindon, 21 October: declination -11.75°, noon altitude 26.69°, zenith 63.31°, geometric daylight 9.974 hours, and vertical-object noon shadow ratio 1.989.
  • Swindon, 21 November: declination -20.44°, noon altitude 18.00°, zenith 72.00°, geometric daylight 8.266 hours, and vertical-object noon shadow ratio 3.078.
  • Swindon, 21 December: declination -23.45°, noon altitude 14.99°, zenith 75.01°, geometric daylight 7.583 hours, and vertical-object noon shadow ratio 3.734.

Harth computed the Swindon fingerprint for latitude 51.5580° with the Cooper declination approximation, 90° - |latitude - declination| at solar noon, centre-to-centre sunrise hour angle and 1 / tan(altitude) shadow ratio. Longitude -1.7812° is retained for a later civil-time conversion; this screen does not perform that conversion. See NOAA's solar calculation details. Atmospheric refraction, terrain, facade azimuth and obstructions remain outside this first-pass comparison.

Sources and method

Location data from the GeoNames GB dump (CC BY 4.0, snapshot 2026-08-31, GeoNames ID 2636389). Regulatory starting point: UK and devolved building-control authorities. Figures are illustrative — verify against the current locally adopted edition for the site. Solar-method context: NOAA Solar Calculation Details; the Harth monthly table uses a simpler declination and geometric-daylight approximation whose stated limitations must be retained.

Frequently asked questions

What does the sun path record for Swindon establish?

The sun path record for Swindon establishes a reproducible discovery point at 51.5580, -1.7812 (GeoNames ID 2636389, administrative area ENG) and a United Kingdom source path. It does not establish a final project value, approval or parcel decision.

What must be replaced before using this sun path workflow for a project in Swindon?

For the sun path record in Swindon, replace the 51.5580, -1.7812 city reference with the surveyed site or parcel, identify the competent local authority, and verify the current documents under Building Regulations and nation-specific Approved Documents or technical handbooks. Record the edition, retrieval date, units, assumptions and named checker before relying on the result.

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