Sunnypatch

How many hours of sun will that spot get? Draw the walls and fences around it, and see every day of the year.

Measure hours of

Site

Shadows on the map are for the chosen date and time.

This is an example: a garden corner in London. To check your own spot:

  1. Search for your address, or use your location.
  2. Click + Wall on the map, click both ends of each wall or fence, and pick its height.
  3. Drag the red pin to the spot you care about. The results update as you go.

These hours, a plan of the walls and the calendar in one picture, to post or send. It leaves out the map and the address.

Hover for values. Click to pick a day.

Show as a table (15th of each month)

Each column is a day; read down for the time. Click to jump the map there.

Hour by hour at the measuring point.

How many hours of sun does a plant need?

Plant labels usually mean: full sun is at least 6 hours of direct sun a day through the growing season, part shade is 3 to 6 hours, and full shade is less than 3. The summary above gives the hours for midsummer, the equinox and midwinter. Hover the year chart for any other day. More in what full sun and part shade mean in hours and how much sun vegetables need.

Which side of a wall or fence gets the most sun?

North of the equator, the south-facing side. South of the equator, the north-facing side. An east-facing side gets the morning sun and a west-facing side the afternoon sun. To compare, draw the wall and press the side button under Measuring point to flip the pin across it. The guide to which side of a fence gets the most sun has the hours for each side.

How far does a fence's shadow reach?

On level ground, a shadow's length is the wall's height divided by the tangent of the sun's height above the horizon. In London at midday on 21 December the sun is about 15° up, so a 1.8 m fence casts a shadow about 6.7 m long. On 21 June it is about 62° up, and the same shadow is under 1 m. Turn on the shade map to see every shadow at once. For other places, see fence shadow lengths by latitude and season.

Does it include trees, houses, hills or cloud?

No. Only the walls you draw cast shade, on level ground, under a clear sky. To include a building, draw its sides as walls at the building's height.

Are the times adjusted for daylight saving?

Yes. Times follow the site's own time zone, which comes from its coordinates, and include summer time. To see standard time all year, open Coordinates and time zone and untick Follow daylight saving.

Can I save or share a site?

Your site is saved in this browser automatically. Copy link gives a link with your walls, their heights and the point, so someone else can open the same site.

  • Level ground, and thin vertical walls of the length you draw. Nothing else casts shade: no trees, buildings or cloud.
  • The sun's position comes from the NOAA solar equations, sampled every 5 minutes (every 10 minutes, one day a week, for the year-average shade map). It is accurate to about 0.1°. The sun is treated as a point, so soft shadow edges and refraction near the horizon are ignored.
  • "Shade" means at least one wall blocks direct sunlight at that spot. "Direct sun" is daylight minus that shade.
  • Distances to the point are measured at right angles to each wall's line, even when the point lies past the end of the wall.
  • Clock times use the site's time zone, with this year's daylight saving dates. The year has 365 days; 29 February is left out.