Solar & Daylight Data
Sun Path: Ruiru, Kenya
How to research sun path for a specific site in Ruiru — 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 KE dump](https://download.geonames.org/export/dump/KE.zip) (CC BY 4.0, snapshot 2026-08-31, GeoNames ID 181032). Regulatory starting point: [National Construction Authority and the applicable county government](https://www.nca.go.ke/). 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 Ruiru at -1.1466, 36.9609, the declination-only solar-noon altitude is approximately 65.4° at the June solstice, 88.9° at an equinox and 67.7° 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 181032 in administrative area 22, at -1.1466, 36.9609; replace it with the surveyed parcel point before relying on the result. As a transparent geometry check, declination-only solar-noon altitude is about 65.4° at the June solstice, 88.9° at an equinox and 67.7° at the December solstice. Representative 21st-day geometry ranges from about 11.9 hours in June to 12.1 hours in December; 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 Ruiru?
Ruiru is represented here at approximately -1.1466, 36.9609 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?
- Fix the surveyed site and local time basis.
- Select an authoritative weather source or a named solar-position algorithm.
- Record period, percentile or scenario and units.
- Test sensitivity to elevation, exposure, urban form and horizon.
- Save the source file, retrieval date and checker in the model record.
| Input | Project-specific evidence | QA question |
|---|---|---|
| Site | surveyed coordinates, elevation and horizon | Does the point represent the building? |
| Weather/solar method | named dataset, algorithm, period and time basis | Are station, time zone and units explicit? |
| Design scenario | current and future scenario agreed by the team | Is an average being mistaken for an extreme? |
| Compliance | adopted local document and edition | Was 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 Ruiru site remain authoritative.
Ruiru monthly solar geometry check for sun path
| Representative date | Declination | Solar-noon altitude | Geometric daylight | Noon shadow / height |
|---|---|---|---|---|
| 21 January | -20.14° | 71.01° | 12.056 h | 0.344 |
| 21 February | -11.23° | 79.92° | 12.030 h | 0.178 |
| 21 March | -0.40° | 89.26° | 12.001 h | 0.013 |
| 21 April | +11.58° | 77.27° | 11.969 h | 0.226 |
| 21 May | +20.14° | 68.72° | 11.944 h | 0.390 |
| 21 June | +23.45° | 65.40° | 11.934 h | 0.458 |
| 21 July | +20.44° | 68.41° | 11.943 h | 0.396 |
| 21 August | +11.75° | 77.10° | 11.968 h | 0.229 |
| 21 September | -0.20° | 89.06° | 12.001 h | 0.016 |
| 21 October | -11.75° | 79.39° | 12.032 h | 0.187 |
| 21 November | -20.44° | 70.71° | 12.057 h | 0.350 |
| 21 December | -23.45° | 67.70° | 12.066 h | 0.410 |
Ruiru solar-geometry fingerprint at -1.1466, 36.9609
- Ruiru, 21 January: declination -20.14°, noon altitude 71.01°, zenith 18.99°, geometric daylight 12.056 hours, and vertical-object noon shadow ratio 0.344.
- Ruiru, 21 February: declination -11.23°, noon altitude 79.92°, zenith 10.08°, geometric daylight 12.030 hours, and vertical-object noon shadow ratio 0.178.
- Ruiru, 21 March: declination -0.40°, noon altitude 89.26°, zenith 0.74°, geometric daylight 12.001 hours, and vertical-object noon shadow ratio 0.013.
- Ruiru, 21 April: declination +11.58°, noon altitude 77.27°, zenith 12.73°, geometric daylight 11.969 hours, and vertical-object noon shadow ratio 0.226.
- Ruiru, 21 May: declination +20.14°, noon altitude 68.72°, zenith 21.28°, geometric daylight 11.944 hours, and vertical-object noon shadow ratio 0.390.
- Ruiru, 21 June: declination +23.45°, noon altitude 65.40°, zenith 24.60°, geometric daylight 11.934 hours, and vertical-object noon shadow ratio 0.458.
- Ruiru, 21 July: declination +20.44°, noon altitude 68.41°, zenith 21.59°, geometric daylight 11.943 hours, and vertical-object noon shadow ratio 0.396.
- Ruiru, 21 August: declination +11.75°, noon altitude 77.10°, zenith 12.90°, geometric daylight 11.968 hours, and vertical-object noon shadow ratio 0.229.
- Ruiru, 21 September: declination -0.20°, noon altitude 89.06°, zenith 0.94°, geometric daylight 12.001 hours, and vertical-object noon shadow ratio 0.016.
- Ruiru, 21 October: declination -11.75°, noon altitude 79.39°, zenith 10.61°, geometric daylight 12.032 hours, and vertical-object noon shadow ratio 0.187.
- Ruiru, 21 November: declination -20.44°, noon altitude 70.71°, zenith 19.29°, geometric daylight 12.057 hours, and vertical-object noon shadow ratio 0.350.
- Ruiru, 21 December: declination -23.45°, noon altitude 67.70°, zenith 22.30°, geometric daylight 12.066 hours, and vertical-object noon shadow ratio 0.410.
Harth computed the Ruiru fingerprint for latitude -1.1466° with the Cooper declination approximation, 90° - |latitude - declination| at solar noon, centre-to-centre sunrise hour angle and 1 / tan(altitude) shadow ratio. Longitude 36.9609° 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.
Where can you explore related guidance?
- Explore all solar data guidance
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- Sun Path: Nairobi, Kenya
- All solar & daylight data guidance for Kenya
Sources and method
Location data from the GeoNames KE dump (CC BY 4.0, snapshot 2026-08-31, GeoNames ID 181032). Regulatory starting point: National Construction Authority and the applicable county government. 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.
Source links
Frequently asked questions
What does the sun path record for Ruiru establish?
The sun path record for Ruiru establishes a reproducible discovery point at -1.1466, 36.9609 (GeoNames ID 181032, administrative area 22) and a Kenya 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 Ruiru?
For the sun path record in Ruiru, replace the -1.1466, 36.9609 city reference with the surveyed site or parcel, identify the competent local authority, and verify the current documents under National Building Code and county development-control requirements. Record the edition, retrieval date, units, assumptions and named checker before relying on the result.
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