# Sun Path & Solar Angles for Boston, MA

> Calculated solar-noon angles and a first-pass fixed-shading worksheet for Boston, MA, using transparent solar geometry rather than an unexplained chart.

- Canonical: https://harth.build/resources/solar-data/sun-path-and-solar-angles-boston-ma/
- Last updated: 2026-08-17
- Data source: Original calculation using latitude 42.3601° N and declinations +23.44°, 0°, and -23.44°. Formula: altitude = 90° - |latitude - declination|. Time zone: America/New_York. Verify occupied-hour positions with the NOAA Solar Calculator; values omit refraction, equation of time, terrain, obstructions, and facade azimuth.

## Key facts

| Fact | Value |
| --- | --- |
| Latitude | 42.3601° N (Boston, MA) |
| June solstice noon | 71.1° (south at solar noon) |
| Equinox noon | 47.6° (geometric solar noon) |
| December solstice noon | 24.2° (geometric solar noon) |

## Direct answer

Calculated solar-noon angles and a first-pass fixed-shading worksheet for Boston, MA, using transparent solar geometry rather than an unexplained chart. A key reference is latitude: 42.3601° N; check the cited source, edition, units, and applicability before using it for design, compliance, procurement, or approval. Latitude is 42.3601° N; Boston, MA. June solstice noon is 71.1°; south at solar noon. Equinox noon is 47.6°; geometric solar noon. Projection ratio = 1 / tan(solar altitude). Multiply the ratio by the vertical distance the noon shadow must cover. Use this only as a hand check before a full-year study. Read the values with the cited source, edition or observation period, units and applicability; replace illustrative inputs with current project evidence before design, procurement or approval use.

*Content and cited inputs reviewed by [Scott Barrington](https://nz.linkedin.com/in/barrington), Harth founder and architectural technology specialist · Published 2026-08-17 · Updated 2026-08-17.*


![Labeled sun-path diagram: Sun Path & Solar Angles for Boston, MA](https://efwwel0vyt9vy5so.public.blob.vercel-storage.com/images/solar-data/sun-path-and-solar-angles-boston-ma/diagram-1344.webp)

*Calculated solar-noon angles and a first-pass fixed-shading worksheet for Boston, MA, using transparent solar geometry rather than an unexplained chart.*

## Which solar conditions control the result?

| Date | Declination | Altitude | Projection / vertical shade distance |
| --- | ---: | ---: | ---: |
| June solstice | +23.44° | 71.08° | 0.343 |
| Equinox | 0° | 47.64° | 0.912 |
| December solstice | -23.44° | 24.20° | 2.225 |

Projection ratio = 1 / tan(solar altitude). Multiply the ratio by the vertical distance the noon shadow must cover. Use this only as a hand check before a full-year study.

## Boston, MA shading record

Record facade azimuth, window head and sill, overhang height, required shaded dates and hours, coordinates (42.3601° N), time zone (America/New_York), calculation method, surrounding obstructions, reviewer and date. Compare the full model against the three noon ratios above and retain screenshots of the critical summer and shoulder-season hours. Verify hourly positions with the [NOAA Solar Calculator](https://gml.noaa.gov/grad/solcalc/).

## Where can you explore related guidance?

- [Explore all solar data guidance](https://harth.build/resources/solar-data.md)
- [Understanding Sun-Path Diagrams](https://harth.build/resources/solar-data/understanding-sun-path-diagrams.md)
- [Solar Altitude and Azimuth Explained](https://harth.build/resources/solar-data/solar-altitude-and-azimuth-explained.md)
- [Climate Design Data Workflow for Boston, MA](https://harth.build/resources/climate-data/climate-design-data-workflow-boston-ma.md)

## Sources and method

Original calculation using latitude 42.3601° N and declinations +23.44°, 0°, and -23.44°. Formula: altitude = 90° - |latitude - declination|. Time zone: America/New_York. Verify occupied-hour positions with the NOAA Solar Calculator; values omit refraction, equation of time, terrain, obstructions, and facade azimuth.

### Source links

- [gml.noaa.gov](https://gml.noaa.gov/grad/solcalc/)

## Frequently asked questions

### What is the sun angle in Boston, MA at the summer solstice?

The declination-only solar-noon altitude is approximately 71.1°. This is a transparent geometry check, not a substitute for an hourly solar-position calculation.

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