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Solar & Daylight Data

Updated 2026-09-02

Daylight & Orientation: Dún Laoghaire, Ireland

How to research daylight & orientation for a specific site in Dún Laoghaire — the controlling authority, source documents, and checks to run before you rely on a number.

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Last updated September 2, 2026 · Location data from the [GeoNames IE dump](https://download.geonames.org/export/dump/IE.zip) (CC BY 4.0, snapshot 2026-08-31, GeoNames ID 2964506). Regulatory starting point: [Department of Housing, Local Government and Heritage and the local building-control authority](https://www.gov.ie/en/department-of-housing-local-government-and-heritage/collections/building-standards/). 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. Project-date refinement reference: [NREL Solar Position Algorithm](https://midcdmz.nrel.gov/spa/).

Direct answer

For Dún Laoghaire at 53.2940, -6.1359, the declination-only solar-noon altitude is approximately 60.1° at the June solstice, 36.7° at an equinox and 13.3° 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 2964506 in administrative area L, at 53.2940, -6.1359; replace it with the surveyed parcel point before relying on the result. As a transparent geometry check, declination-only solar-noon altitude is about 60.1° at the June solstice, 36.7° at an equinox and 13.3° at the December solstice. Representative 21st-day geometry ranges from about 7.3 hours in December to 16.7 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 daylight and building orientation record.

Prepared by Harth · Topic-specific calculated asset and fresh SERP brief passed editorial screening; page remains noindex pending the independent content, evidence, similarity and link gates · Published 2026-08-26 · Updated 2026-09-02.

What must be verified for Dún Laoghaire?

Dún Laoghaire is represented here at approximately 53.2940, -6.1359 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 daylight and building orientation 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 daylight-workflow page is a project-starting worksheet, not a design value or approval. The controlling authority and qualified professionals for the Dún Laoghaire site remain authoritative.

Dún Laoghaire monthly daylight-orientation ledger

Representative dateGeometric daylightSolar sunriseSolar sunsetSunrise hour angleNoon bearingChange from prior month
21 January8.072 h07.9616.0460.54°180.0°+0.815 h
21 February9.941 h07.0316.9774.56°180.0°+1.870 h
21 March11.928 h06.0417.9689.46°180.0°+1.986 h
21 April14.127 h04.9419.06105.95°180.0°+2.199 h
21 May15.928 h04.0419.96119.46°180.0°+1.802 h
21 June16.744 h03.6320.37125.58°180.0°+0.815 h
21 July15.999 h04.0020.00120.00°180.0°-0.744 h
21 August14.161 h04.9219.08106.21°180.0°-1.839 h
21 September11.964 h06.0217.9889.73°180.0°-2.197 h
21 October9.839 h07.0816.9273.79°180.0°-2.125 h
21 November8.001 h08.0016.0060.00°180.0°-1.839 h
21 December7.256 h08.3715.6354.42°180.0°-0.744 h

Orientation checks prompted by the Dún Laoghaire ledger

The representative daylight span runs from 7.256 hours on 21 December to 16.744 hours on 21 June. Solar sunrise and sunset are expressed in apparent solar time, not a time-zone clock. The noon-bearing column is a true-north azimuth screen and becomes unstable when the sun passes close to zenith.

For Dún Laoghaire at 53.2940°, -6.1359°, test each occupied facade against the actual horizon, adjacent buildings, glazing, room depth and target illuminance. This ledger describes geometric availability only; it does not estimate irradiance, daylight autonomy, glare or energy. Refine project-date positions with the NREL SPA.

Where can you explore related guidance?

Sources and method

Location data from the GeoNames IE dump (CC BY 4.0, snapshot 2026-08-31, GeoNames ID 2964506). Regulatory starting point: Department of Housing, Local Government and Heritage and the local building-control authority. 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. Project-date refinement reference: NREL Solar Position Algorithm.

Source links

Frequently asked questions

What does the daylight and building orientation record for Dún Laoghaire establish?

The daylight and building orientation record for Dún Laoghaire establishes a reproducible discovery point at 53.2940, -6.1359 (GeoNames ID 2964506, administrative area L) and a Ireland source path. It does not establish a final project value, approval or parcel decision.

What must be replaced before using this daylight and building orientation workflow for a project in Dún Laoghaire?

For the daylight and building orientation record in Dún Laoghaire, replace the 53.2940, -6.1359 city reference with the surveyed site or parcel, identify the competent local authority, and verify the current documents under Building Regulations and Technical Guidance Documents. Record the edition, retrieval date, units, assumptions and named checker before relying on the result.

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