Sunset forecasting · pick your sky

Clear skies aren't the goal.
The right clouds are.

For anyone who has driven to a viewpoint for nothing: pick tonight's sky, see which method calls it.

Tap the sky that looks most like yours.

We'll show what looking up, the cloud layers and the horizon toward the Sun each predict.

Download Asterfold: Sunset Planner on the App StoreFree on iPhone · works for tonight

How do you predict a good sunset?

Check two things, not one: whether there is mid or high cloud over roughly a third to two thirds of the sky, and whether the western horizon toward the setting Sun is clear of low cloud. If both are true, the clouds above you can catch the light. If the horizon is blocked, even a perfect-looking sky usually goes grey.

That is why looking up is the least reliable method. The cloud that decides your sunset is often a long way off, between you and the Sun, where you cannot judge it from the ground.

The sky above you is the stage. The horizon toward the Sun is the light switch.

Four ways to predict a sunset, compared

01

Look up

Free and instant. Tells you about overhead cloud, which matters, but misses low cloud near the horizon. The method most likely to send you out on a night that fizzles.

02

Read the cloud layers

Any detailed forecast that splits low, mid and high cloud. SunsetHue's guide to predicting sunsets suggests about 40 to 60 percent mid and high cloud with no cloud on the western horizon; Alpenglow says 30 to 70 percent mid-to-high. Clean, dry air helps too.

03

Check toward the Sun

The step most people skip: what is the low cloud doing tens of kilometres away, in the direction of sunset? That is the path the light travels. Asterfold checks point forecasts 60 km and 180 km toward the setting Sun for tonight.

04

Use a sunset forecast

Services like SunsetHue and Alpenglow turn the cloud data into a score for your location. Fast, and good on the day. All of them, ours included, are estimates.

Method vs method: a comparison strip

MethodCatches overhead cloudCatches low cloud toward the SunEffort
Look upYesRarelyNone
Cloud layers forecastYesOnly at your spotA few minutes
Toward the SunPartlyYesHard by hand
Sunset forecast app or siteYesDepends on the serviceSeconds

Combine methods 2 and 3 and you have most of what a sunset forecast does.

Proof: how Asterfold shows tonight

Asterfold Tonight screen with Sunset, Stars and Sunrise ratings labelled as estimates and plain-English reasons
Tonight: ratings labelled as an estimate, with reasons.
Asterfold field journal asking How did the sunset turn out? with ratings from Grey to Unforgettable
After sunset: rate what you saw in two taps.
Asterfold Light Path Studio sky dome showing the Sun's path for a place and date
The Sun's path for any place and date, offline.

The Tonight screen shows hour-by-hour low, mid and high cloud from MET Norway, the two points toward the setting Sun, golden hour, blue hour, the Moon and planets. After sunset, the field journal compares your check-in with the forecast Asterfold saved before the sunset, never a later one. After three check-ins, your colour ratings adjust to your own sky in small, capped steps.

One design decision we made: calculated, forecast, estimated and observed data are labelled differently everywhere in the app. A sunset time is maths. A colour rating is a guess. We never want the two to look the same.

Who this is not for

  • Anyone who needs certainty. No method guarantees colour. If you are booking a once-only shoot, plan a backup evening.
  • Mountain and city-canyon viewpoints. Asterfold's Sun positions assume a flat horizon; hills, buildings and trees are not modelled.
  • Android users. Asterfold is iPhone only. SunsetHue's website works in any browser.
  • Long-range planners. Free covers the next 3 evenings; the full 10-day outlook and smart sky alerts are part of Asterfold Plus (yearly with a 7-day free trial for eligible new subscribers, monthly, or lifetime).

Sunset prediction questions

How can you tell if a sunset will be colorful?

Look for mid or high cloud covering part of the sky, roughly a third to two thirds of it, with a clear western horizon so sunlight can reach the underside of those clouds. SunsetHue suggests about 40 to 60 percent mid and high cloud; Alpenglow says 30 to 70 percent. Thick low cloud toward the sunset usually blocks the colour.

Are clear skies good for sunsets?

A clear sky gives a clean orange-to-blue gradient near the horizon, which is lovely for silhouettes and blue hour. It rarely gives the whole-sky fiery colour, because there is no cloud overhead to catch the light.

What clouds make the best sunsets?

High, thin clouds such as cirrus are often the best because they sit high enough to stay lit after the Sun has gone below your horizon. SunsetHue notes high clouds can stay painted in warm colours for up to 30 minutes after sunset.

Why did the sunset go grey when the sky looked great?

Usually a bank of low cloud sat on the western horizon, between you and the setting Sun. From where you stand it can look like a thin dark line, but it blocks the light that would have lit the clouds overhead.

How far ahead can you predict a sunset?

Cloud forecasts are most useful on the day. A day or two out they give a rough idea; beyond that, treat any sunset rating as a guess. Check again in the afternoon.

Does Asterfold guarantee a good sunset?

No. Its Sunset, Stars and Sunrise ratings are labelled as a rule-of-thumb estimate, not a probability or a guarantee. Sun positions assume a flat horizon, so hills, buildings and trees are not modelled.

Is Asterfold free?

Free includes the Light Path Studio, aiming and plans for 2 viewpoints, the journal, check-ins and tuning, tonight's ratings, the next 3 evenings and 45 days of events. Asterfold Plus adds unlimited viewpoints, smart sky alerts, the full 10-day outlook and a year of sky events.

Try it tonight.

Check the clouds, check toward the Sun, then log what the sky really did.

Download Asterfold: Sunset Planner on the App Store

Try Asterfold tonight on the App Store · Updated November 2026

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