Sun Path: Patna, India

Direct answer

For Patna at 25.5941, 85.1356, the declination-only solar-noon altitude is approximately 87.8° at the June solstice, 64.4° at an equinox and 41.0° 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 1260086 in administrative area 34, at 25.5941, 85.1356; replace it with the surveyed parcel point before relying on the result. As a transparent geometry check, declination-only solar-noon altitude is about 87.8° at the June solstice, 64.4° at an equinox and 41.0° at the December solstice. Representative 21st-day geometry ranges from about 10.4 hours in December to 13.6 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.

Content and cited inputs reviewed by Scott Barrington, Harth founder and architectural technology specialist · Published 2026-08-26 · Updated 2026-08-31.

What must be verified for Patna?

Patna is represented here at approximately 25.5941, 85.1356 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.

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 Patna site remain authoritative.

Patna monthly solar geometry check for sun path

Month-by-month geometry interpretation

• 21 January: approximate solar-noon altitude 44.3° (zenith angle 45.7°) and 10.7 hours of geometric daylight. That is 0.3 hours longer than the preceding representative date in this annual sequence.
• 21 February: approximate solar-noon altitude 53.2° (zenith angle 36.8°) and 11.3 hours of geometric daylight. That is 0.6 hours longer than the preceding representative date in this annual sequence.
• 21 March: approximate solar-noon altitude 64.0° (zenith angle 26.0°) and 12.0 hours of geometric daylight. That is 0.7 hours longer than the preceding representative date in this annual sequence.
• 21 April: approximate solar-noon altitude 76.0° (zenith angle 14.0°) and 12.8 hours of geometric daylight. That is 0.8 hours longer than the preceding representative date in this annual sequence.
• 21 May: approximate solar-noon altitude 84.5° (zenith angle 5.5°) and 13.3 hours of geometric daylight. That is 0.6 hours longer than the preceding representative date in this annual sequence.
• 21 June: approximate solar-noon altitude 87.9° (zenith angle 2.1°) and 13.6 hours of geometric daylight. That is 0.3 hours longer than the preceding representative date in this annual sequence.
• 21 July: approximate solar-noon altitude 84.8° (zenith angle 5.2°) and 13.4 hours of geometric daylight. That is 0.2 hours shorter than the preceding representative date in this annual sequence.
• 21 August: approximate solar-noon altitude 76.2° (zenith angle 13.8°) and 12.8 hours of geometric daylight. That is 0.6 hours shorter than the preceding representative date in this annual sequence.
• 21 September: approximate solar-noon altitude 64.2° (zenith angle 25.8°) and 12.0 hours of geometric daylight. That is 0.8 hours shorter than the preceding representative date in this annual sequence.
• 21 October: approximate solar-noon altitude 52.7° (zenith angle 37.3°) and 11.2 hours of geometric daylight. That is 0.7 hours shorter than the preceding representative date in this annual sequence.
• 21 November: approximate solar-noon altitude 44.0° (zenith angle 46.0°) and 10.6 hours of geometric daylight. That is 0.6 hours shorter than the preceding representative date in this annual sequence.
• 21 December: approximate solar-noon altitude 41.0° (zenith angle 49.0°) and 10.4 hours of geometric daylight. That is 0.2 hours shorter than the preceding representative date in this annual sequence.

Harth calculation for latitude 25.5941°: Cooper declination approximation, 90° - |latitude - declination| at solar noon, and centre-to-centre sunrise hour angle. See NOAA's solar calculation details for fuller method context. This screening table excludes equation-of-time/civil-time conversion, atmospheric refraction, terrain, facade azimuth and obstructions; it is not an hourly shading result.

Where can you explore related guidance?

• Explore all solar data guidance
• Sun Path: Varanasi, India
• Sun Path: Dhanbad, India
• Sun Path: Jamshedpur, India
• Sun Path: Lucknow, India
• All solar & daylight data guidance for India
• Climate Design Data: Patna, India
• House Construction Cost Planning: Patna, India
• Office Construction Cost Planning: Patna, India
• Retail Construction Cost Planning: Patna, India

Sources and method

Location data from the GeoNames IN dump (CC BY 4.0, snapshot 2026-08-31, GeoNames ID 1260086). Regulatory starting point: Bureau of Indian Standards and the applicable state or urban local body. 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

• download.geonames.org

• services.bis.gov.in

• gml.noaa.gov