Sun path and radiation
Set the exact site, read the sun path diagram in solar or clock time, the solstice and equinox table, and monthly solar radiation.
Site location #
The Site location card sets the point the sun angles are computed for. It shows the site's name and coordinates, and how far it is from the weather station. With no site set, Sun Path uses the station's location and says so.
Set or change the site in any of these ways:
- By address. Type in Site address and click Find, then pick the right place from the list.
- By coordinates. Type latitude, longitude in decimal degrees (west is negative) and click Use coordinates.
- On the map. Click the map in the card to drop the site pin.
Use the station's location clears the site and goes back to the station.
The site is saved with the scheme. Viewers on the project see it but can't change it. Address search sends only what you type to OpenStreetMap's geocoder, when you click Find.
The sun path diagram #
The Sun path card is a view looking straight up: the center is overhead, the outer circle is the horizon, and north is at the top. Each curve is the sun's path on the 21st of a month.
Solar time or clock time #
The two buttons above the diagram set how hours are shown:
- Solar time: 12 is solar noon, when the sun is due south (north of the tropics). It differs from the clock by the time zone offset, daylight saving and up to about 16 minutes through the year.
- Clock time: the clock in the site's time zone. Sun Path finds the zone from the coordinates on your device, with no lookup service. Each dashed figure-eight is one clock hour through the year.
In clock time, the card names the time zone and its offset. Where the zone observes daylight saving, tick or untick Use daylight saving. With it on, an hour line breaks where the clocks change.
Near a time-zone border the boundary data can be a few miles off, so check the zone it names. The choice is a setting on this device, not part of the scheme.
Solstices and equinoxes #
The table has one row each for the solstices and equinoxes:
- Noon altitude: how high the sun is at solar noon, in degrees.
- Daylight: hours and minutes of daylight.
- Sunrise → sunset: in solar time, or in clock time when Clock time is on.
- Solar noon (clock): shown in clock time, with the offset.
- Rises / sets at: the direction of sunrise and sunset, in degrees clockwise from true north (90° is east, 270° is west).
Reading it for design: the winter noon altitude sets how deep low sun reaches into south rooms; the summer noon altitude sizes a south overhang; the summer rise and set directions show the low east and west sun an overhang can't stop.
Sun positions use the NOAA Solar Calculator equations, computed for the site's latitude and longitude.
Solar radiation by month #
This card comes from the weather station, not the site. It gives the yearly total on open level ground in kWh/m², the sunniest and dimmest months, and two charts in kWh/m² a day:
- Global horizontal: direct plus diffuse sun on a level surface.
- Direct normal: the direct beam, when the station has it.
It's the station's typical year on a level surface. Orientation, tilt, shading and dirt change what a roof or wall receives: it isn't a solar-panel yield estimate. If the station has no radiation data, the card says so; the sun path doesn't need it.
The charts follow the Colors setting above the study. See Chart colors.