Plan the sun.
Check the actual light.

A time is incomplete without a place and date

Start with the exact place you intend to visit, not a similarly named town or your phone's current location. Write down the selected coordinates or map point, the visit date and the time zone used by the calculation. If you are planning while travelling, the destination's local clock and your phone's current clock may differ.

A named time zone can have a different UTC offset on different dates. For a future or historical plan, verify the offset for the selected date, including any daylight-saving change. Do not silently reuse today's offset. Record a local time in an unambiguous format, such as 18:00, and keep the offset beside it.

The offsets above are arbitrary worksheet assumptions; they do not establish the rules for any real destination. Around a clock change, a local time can be ambiguous or absent. If your tool cannot represent it clearly, choose an unambiguous time and record the issue instead of guessing.

If you enter coordinates manually, check the tool's north/south and east/west sign convention. A copied number with the wrong sign points to a different place. Save or write down the inputs with the result so you can reproduce the plan later.

Direction and height are different questions

Azimuth describes direction around the horizon. In the common convention used by the NOAA reference below, it increases clockwise from north: east is 90°, south 180° and west 270°. Elevation describes the angle above the horizon. Check the convention in the tool you use before comparing values.

These are solar angles, not a model of the objects between you and the sun. A positive solar elevation does not establish that a building, tree or ridge is out of the way. Likewise, a published sunset time is not necessarily the moment sunlight disappears behind the building opposite your patio.

Keep directional references consistent. A map direction and a phone compass reading need not use the same north reference; consult the tool's settings or documentation rather than treating a hand-held heading as a precise survey. For an ordinary photograph, describe the intended viewpoint and subject as well as the bearing.

Never look directly at the sun to verify a calculated direction. This worksheet is not a solar-viewing procedure or a guide to pointing optical equipment at the sun.

On site, record what you actually observe

1. Confirm the viewpoint. “At the west edge of the patio, facing the table” is more reproducible than “in the garden.” Only enter or photograph places where you have appropriate permission.
2. Record the observation time separately. Keep the local date, time and offset. A plan saved yesterday is not evidence of yesterday's observed weather.
3. Describe obstacles and conditions. Note the visible trees, buildings or terrain that matter from that viewpoint, plus whether the sky is clear, partly cloudy or overcast. Do not invent heights, distances or an obstruction model.
4. Describe the result narrowly. “Table surface in shade at the observed time” is useful. “This patio never gets sun” is not established by one visit.
5. Keep uncertainty visible. If the clock, exact point or visibility was uncertain, say so. If you could not visit, label the record planned, not observed.

A few permitted reference photographs and a short note can help you return to a similar viewpoint. Avoid faces, addresses, access details and other unnecessary personal information when sharing them. This is a manual field-note method; it does not imply the optional app stores photographs or calculates obstacle geometry.

Change one thing, and retain the reason

Comparing two dates can help plan a later visit, but hold the place and intended local observation time constant first. Write down any changed offset, viewpoint or condition. If several inputs change at once, the difference cannot be attributed to the season alone.

Scroll sideways on a narrow screen. These are manual worksheet labels, not extra app fields or calculated site measurements.

Before sharing a plan, open the actual exported file and check the point, selected date (or both dates if comparing), time zone and selected time. A recipient should be able to distinguish a planned calculation from a field observation without asking you to reconstruct the context.

A copyable sunlight field note

For a quick start, keep just four things: the place, date/time/zone, planned or observed, and what was actually lit or shaded. Use the fuller optional record below when you need to repeat or share the visit.

Use paper or your own private document. No account, email address or app download is required.

Purpose / subject:
Place / chosen map point or coordinates:
Coordinate sign convention checked:
Viewpoint / facing direction / north reference:

PLAN:
Selected date / intended local time:
Named time zone / UTC offset for that date:
Clock-change ambiguity checked:
Tool / calculated direction and elevation:
Other date compared / changed inputs:
Saved plan or export reference:

OBSERVATION (leave unknowns explicit):
Actual local date / time / UTC offset:
Same viewpoint? If not, what changed:
Sky conditions / visible obstacles:
What was lit or shaded at that time:
Permission / privacy checks for any photographs:
Uncertain clock, position or visibility:

Next visit / unanswered question:
Actual shared file checked / revision:
Planned versus observed clearly labelled:

Reference, not a promise of accuracy

The NOAA solar-position reference explains azimuth and elevation units. Its old calculator uses a non-standard west-positive coordinate/time-zone convention; do not copy those input conventions into another tool. The NOAA calculator page discusses time-zone checks and observed-versus-calculated differences, and now states that the calculator is no longer actively supported or maintained. These links are background references, not a current accuracy certification or endorsement of our app.

This worksheet does not model shadows, assess daylight regulations, determine plant suitability or solar-panel output, predict weather, or replace a qualified site assessment. One visit does not establish seasonal exposure. Use the tool as a starting point for an ordinary outdoor plan, not a guarantee of direct light.