How golden hour is calculated
The sun's timing is pure astronomy — exact, repeatable, the same every year. Here's how Golden Hour turns your location into precise times, and how the shoot score reads the weather on top of them.
When is golden hour?
Golden hour isn't a fixed clock time. It's defined by how high the sun sits — its altitude above the horizon — so it shifts with your latitude and the season.
- Golden hour — sun from about +6° down to roughly −4°. Low, warm, raking light with long shadows.
- Blue hour — sun from about −4° to −6°. The sky glows cool and even after the sun has dropped away.
- Sunrise & sunset — the moment the sun's upper edge meets the horizon: officially −0.833°, not 0°, because the atmosphere bends the light and the sun has width of its own.
- Civil twilight — ends at −6°: still bright enough to get around without lights.
How this app calculates it
Golden Hour uses suncalc, an implementation of the algorithms in Jean Meeus's Astronomical Algorithms— the standard reference for this math. (NREL's Solar Position Algorithm, the SPA, is the rigorous gold standard, accurate to ±0.0003°; Meeus lands within about an arcminute, far finer than anyone needs to plan a shoot.)
From your latitude, longitude and the date, it tracks the sun's position through the day, finds the instants it crosses each altitude boundary above, and shows them in your location's local time — accurate to about a minute. The solar math runs in your browser; saved places stay on this device. No account is required.
The shoot score
Timing is exact. Whether the light is actually good is weather — so the shoot score blends the two. For the upcoming golden hour, it pulls the hourly forecast from Open-Meteo (cloud cover split into low, mid and high layers, rain and shower risk, plus visibility) and turns it into a 0–10 score:
- Some high or mid cloud (~25–65%) — ideal. Those are the clouds that catch and scatter color.
- Heavy low cloud, fog or haze — flattens the light and blocks the sun at the horizon. Big penalty.
- Active rain or likely showers — lowers the score for usability, while still leaving room for post-rain color.
- Dead-clear sky — reliable but rarely dramatic, so it lands around 6, not 10.
It's a forecast, not a guarantee. Weather moves, and the best skies often come from cloud that arrives — or clears — at the last minute. Treat the score as a nudge, not a promise.
Golden vs blue hour
- Golden hour — sun +6° to −4°. Warm and directional, long shadows. Best for portraits and landscapes.
- Blue hour — sun −4° to −6°. Cool, even, glowing. Best for cityscapes and lit windows against a deep-blue sky.
Planning FAQ
Quick answers before you head out
When is golden hour?
Golden hour is the low-angle light after sunrise and before sunset. Golden Hour calculates the morning and evening windows for the selected place, date, and timezone.
Does the shoot score include rain?
Yes. The score reads cloud layers, visibility, active rain, and shower risk. Rain can lower the score even when the timing is perfect, because wet weather changes how practical the shoot will be.
Can I plan golden hour for a future date?
Yes. Pick a future date to see that day’s golden hour, blue hour, sunrise, sunset, and solar noon. You can copy a planned-date link or add morning and evening reminders to your calendar.
Can I save places without an account?
Yes. Saved places stay on this device, so you can jump back to frequent shoot locations without creating an account or signing in.
Why should I check again before leaving?
The sun times are stable, but weather is not. Rechecking close to the shoot helps catch moving cloud, rain, fog, haze, or a clearing horizon before you commit the trip.
Are email golden-hour alerts live?
The alert workflow is built behind a feature flag while database storage and email delivery are being connected. Today, you can still use saved places, shareable plans, and calendar reminders without an account.