How to Read an ISS Pass

Published October 12, 2026 · Updated October 12, 2026

A pass comes down to five details

When you turn on your location in our tracker, the “Next pass over you” card shows something like this: 9:14 p.m. · today · 5 min · max. 62° · W → E, plus a visibility bar and a countdown. It looks like a lot, but each item answers a very specific question: when it starts, how long it lasts, how high it climbs, and where it comes in and goes out.

Below it, under “More passes,” you'll see the rest of the passes over the next 24 hours in the same format. This guide explains how to read them and, above all, how to pick the ones worth going outside for.

Time and duration

The time is the moment the station climbs above 8° of height over your horizon. Below that, buildings, trees or haze almost always block it, so there's no point starting the clock any earlier. It's shown in your device's time and rounded to the minute, so it's a good idea to start looking a couple of minutes early.

The duration is how long it stays above those 8°. Low passes last two or three minutes; passes that go nearly overhead last up to six or seven. Keep in mind that the duration covers the whole track, but the visible part can be shorter if the station enters Earth's shadow partway across.

Max height: the most important number

Height (or elevation) is measured in degrees up from the horizon: 0° is the horizon and 90° is the point directly over your head. The “max.” figure is the highest the ISS will get on that pass.

The higher, the better: it's closer to you, it shines brighter and nothing gets in the way. At 90°, the station is about 400 km (250 miles) from you; at 10° above the horizon, about 1,500 km (930 miles). That's why a 70° pass can be spectacular while a 12° pass can slip by unnoticed.

You don't need any instruments to measure degrees. Your hand will do, held at arm's length:

A 30° pass goes by about three fists above the horizon. A 60° pass, six fists: two-thirds of the way to straight overhead, which is already very high.

Direction: where it comes from and where it goes

“W → E” means it appears in the west and disappears in the east. We use the eight points of the compass: N, NE, E, SE, S, SW, W and NW. In the small sky chart next to the card you'll see the track drawn out: the edge is the horizon, the center is straight overhead and the arrow shows which way it's moving.

Astronomers also use azimuth, which is the same direction expressed in degrees: 0° is north, 90° east, 180° south and 270° west. If an app says the ISS appears at an azimuth of 250°, it means west-southwest.

Because the ISS orbits in the same direction the Earth spins, from anywhere in the US or Europe it always comes in from somewhere in the west and leaves toward the east. If it rises in the NW, the pass will cross the northern part of the sky; if it rises in the SW, the southern part.

Visibility: what it measures and what it doesn't

The visibility bar turns the max height into a percentage: 90° is 100%. Above 60%, a pass is rated Good; between 30% and 60%, Fair; and below that, Low. It's a quick way to compare passes with each other.

What the bar doesn't take into account is light. To see the station with the naked eye, you have to be in the dark while it's still lit by the Sun, and that only happens in the hour and a half to two hours after dusk and before dawn (in summer, sometimes all night long). You won't see a “Good” pass at 4 p.m. because it's daytime, and you probably won't see one at 3 a.m. in winter either, because the ISS will be in Earth's shadow.

How to pick a pass worth watching

1. Check the time first. Look for passes that fall shortly after dusk or shortly before dawn.
2. Then the height. From 40° up, passes are easy to see; above 60°, they're spectacular.
3. Check which side of the sky. If it stays low, make sure the horizon is clear on the side it crosses.
4. Be ready a couple of minutes early. At first it will look low and faint; it gets brighter as it comes closer.

If you'd like a dry run, the tracker's “Simulate pass” button shows you the track on the map before it happens, and the “AR camera” tells you where to point your phone. To find out how we work all this out, see how we calculate ISS passes.

Frequently asked questions

What does “max. 45°” mean on an ISS pass?

That at its highest point the station will be 45 degrees above the horizon, halfway between the horizon (0°) and straight overhead (90°). That's about four and a half fists at arm's length.

What is azimuth?

The direction to look in, measured in degrees clockwise from north: 0° is north, 90° east, 180° south and 270° west.

Why can't I see a pass with good visibility?

Because the percentage only measures how high it goes. If the pass happens during the day, or in the middle of the night when the ISS is in Earth's shadow, you won't see it even if it goes right overhead.

At what height does a pass start?

In our tracker, at 8° above the horizon. Below that, obstacles and haze almost always hide it. Other sites use 10°, which is why times can differ by a minute.

How long does an ISS pass last?

Between two and seven minutes above 8°, depending on how high it climbs. The visible part can be shorter if it enters Earth's shadow partway across.