New York Elevation ToolsOpen Sunlight on the map →

Terrain · Select a property, draw a box or polygon, or upload a boundary

Winter sun hours on any New York lot

See the winter sun hours on a lot in New York before you buy or build. The tool traces the sun across any day of the year in 15-minute steps and checks whether terrain up to 1.86 mi away block it.

December 21, the shortest day, is the test that matters for a house site: a lot can look sunny at a July showing and lose the sun behind a ridge or a stand of firs by early afternoon in winter. South-facing ground gets the most.

Hours of direct sun on December 21, bright on south-facing slopes and dark on the shaded north side
Sunlight on Mount Marcy. The walkthrough below shows how this was made.

Free to run · pay to download

See the full result on the map free, with no account. Download the sun-hours grid as a GeoTIFF with a pass: US$29 for 24 hours, US$99 for 30 days or US$399 for 12 months, a one-off payment in US dollars that never renews. Every download on the site is included while the pass lasts.

Open Sunlight on the map →Pass prices and what’s included

Who uses this

  • Buyers. Check winter sun on a lot before a summer showing fools them.
  • Architects. Place living areas, decks and windows where the winter sun actually reaches.
  • Growers and solar installers. Find frost pockets and the ground that stays lit in December.

When to use it

  • Checking winter sun on a house site, a deck or a garden before you buy or build.
  • Comparing sunny and shaded parts of a property for planting or livestock.
  • Seeing when the sun first reaches a valley floor and when it leaves.

Tools for your job

Sunlight is one step in a bigger question. These are the jobs it helps with, and the tools that go with it.

For the job: Solar panels and sun

Where will panels, a greenhouse or a deck get the most sun?

  1. 1.Sunlight (this tool) — Hours of direct sun on any date, with terrain shadows from up to 1.86 mi away. Start with December 21.
  2. 2.Slope & Aspect — The aspect view shows which faces point south, and the slope view how steep the mounting ground is.
  3. 3.Find Matching Areas — Highlights the ground that is flat enough, faces the right way and gets a minimum of winter sun, all at once.

For the job: Choosing a house site

Where on this property should the house go?

  1. 1.Find Matching Areas — Narrows the property to the patches that are flat, sunny and facing the right way.
  2. 2.Slope & Aspect — Shows where the ground is easy to build on and where retaining walls will be needed.
  3. 3.Sunlight (this tool) — Checks winter sun on the candidate pad, hour by hour.
  4. 4.Cut & Fill — Estimates the excavation to level the pad before you ask for bids.
  5. 5.Viewshed — Shows what the house will see and who will see it.

For the job: Farms, ranches, orchards and timber

Which ground suits which use?

  1. 1.Slope & Aspect — Equipment limits and erosion-prone slopes.
  2. 2.Sunlight (this tool) — Frost pockets and shaded slopes in winter.
  3. 3.Wetness Map — Wet-tolerant planting in the blue, drought-tolerant on the tan.
  4. 4.Landforms — Exposed ridges, sheltered hollows and well-drained spurs.

How to use it

  1. Select a property, draw an area or upload a boundary.
  2. Pick a date: December 21 (the shortest day), an equinox, June 21 (the longest day), or any date you type.
  3. This edition models terrain shadows only; inspect buildings and trees separately.
  4. Run. Read total hours and first and last sun, then step through the day at half-hour marks to watch the shadows move.
  5. Download the sun-hours grid as a GeoTIFF for GIS. Downloading needs a pass.

Step by step: Mount Marcy

We model December 21, the shortest day, across the Mount Marcy summit area.

The Sunlight panel with an area selected over the Mount Marcy summit area
1.Zoom to the area or select a property. December 21 is the default, because winter sun is the test that matters for a house.
Hours of direct sun on December 21, bright on south-facing slopes and dark on the shaded north side
2.Preview on map. The panel shows the hours of daylight that day, the mean hours of direct sun and the share that gets at least three hours, and when the sun first reaches the area and when it leaves, in Eastern time. The dark areas sit in terrain shadow.
Sunlit and shaded ground at 9:30 am on December 21
3.Choose Step through and move the slider to see each half hour, in Eastern time. Gold ground is in direct sun at that moment, dark ground is in shade.

What it showed

  • South-facing slopes with an open southern horizon get the most winter sun; north-facing canyon walls stay in shadow for much of the day when the sun is this low.
  • Inspect forest and neighboring buildings separately; this edition models terrain shadows only.

Screenshots from New York Elevation Tools. Imagery: Esri, Maxar, Earthstar Geographics, and the GIS User Community. Elevation data from USGS 3D Elevation Program. USGS 3DEP data is in the public domain (U.S. Government work).

Try it yourself on Mount Marcy →

How it works

The sun’s position is computed for the chosen date every 15 minutes. For every cell the tool traces a ray toward the sun and checks whether any terrain within 1.86 mi rises above it. If nothing blocks the ray, the cell is lit for that step.

Hours of sun add up the lit 15-minute steps. Bare-earth terrain supplies the blocking surface.

Reading the results

December 21 is the test that matters for a house site. A south-facing slope with an open southern horizon will show the most hours.

First and last sun are the clock times, in Eastern time, when the sun first clears and finally drops behind the horizon for that cell.

Limits and caveats

  • Direct sun only. Cloud, haze, smoke and diffuse light are not modeled.
  • Shadows from anything further than 1.86 mi away, such as a distant ridge, are ignored. In deep canyons the true horizon may be further out.
  • Bare-earth terrain only. Buildings and trees are excluded from analysis.
  • Times are shown in Eastern time across New York.

Data and attribution

Results come from the USGS 3D Elevation Program (3DEP) bare-earth elevation model: lidar at 3.3 ft per pixel where it has been flown, and the 1/3 arc-second model, about 33 ft per pixel, elsewhere, with elevations above NAVD 88. This edition uses bare-earth terrain only. Buildings and trees are excluded.

USGS 3DEP elevation and USGS maps are U.S. Government works in the public domain. Credit the USGS 3D Elevation Program. NYS public tax parcels are assessment data provided as is, not surveys. Esri World Imagery follows its own terms and is display-only; downloaded aerial imagery comes from USGS NAIP.

Questions

Does it include shade from trees and neighboring houses?

No. This edition models bare-earth terrain shading only. Inspect trees and neighboring buildings separately.

Does it account for clouds?

No. It models direct sun on a clear day. Cloud, haze, wildfire smoke and diffuse light are not included.

What time zone are the times in?

Eastern time, on standard or daylight saving time as it applies on the chosen date, everywhere in the state.

Ready to try it?

Open Sunlight on the map →

Free to use, no account. The analysis runs in your browser on public-domain USGS 3DEP data. Downloading the results needs a pass: see pricing.