¿A QUÉ HORA PASA LA ISS HOY?

What time does the ISS pass over your city today?

It's one of the most searched questions about the International Space Station, and the short answer is: it depends on the day, and it has to be calculated. There's no fixed timetable like a bus schedule, because the ISS doesn't repeat the same pattern over a given point every 24 hours. But you can know it down to the minute using the station's real orbital data — which is exactly what this page helps you do.

Why there's no fixed schedule

The ISS orbits Earth every 90-93 minutes, completing about 16 laps a day at 27,600 km/h (17,150 mph). If Earth stood still, every pass would repeat at regular intervals. But it doesn't: Earth rotates beneath the ISS's orbit, and that orbit is also inclined 51.6 degrees to the equator. Combine both movements and every lap flies over a different strip of the planet's surface than the one before.

In practice, that means the pass time over your city shifts a little each day — usually a few minutes earlier or later than the day before — and, more importantly, not every pass is visible. The ISS is only visible when it's dark at your location while the station, 400 km up, is still catching sunlight. That's the specific overlap of conditions that has to be calculated, and it's different for every latitude and every date of the year.

How it changes with the season

Here's the part that surprises most people searching "what time does the ISS pass" hoping for one single answer: visibility comes in streaks. During certain weeks of the year your city can have visible passes almost every night, some bright and several minutes long. And those streaks are followed by other weeks — sometimes a whole month — with zero visible passes, even though the ISS is still flying over your area just as often: it's simply doing it in broad daylight or in the dead of night, when it's also in darkness.

This depends on the geometry between your latitude, the orbital inclination, and the Sun's position through the year. That's why a static "ISS schedule" table would go stale within days. The only reliable approach is checking an up-to-date calculation right before you step outside to look.

What data you need to know the exact time

Knowing "what time it passes" isn't enough on its own — to actually spot it in the sky you need three pieces of data that always travel together:

• Start time and duration. The exact moment the ISS clears the horizon and how long it stays visible, typically 1 to 6 minutes.
• Maximum elevation. How high it climbs above the horizon, in degrees (0° = ground level, 90° = directly overhead). The higher it goes, the better and longer the pass.
• Appearance and disappearance direction. The compass point it rises from and sets toward, so you know where to look throughout the pass.

These three numbers only come from processing the ISS's latest orbital elements (TLE) together with your exact geographic position. It's an orbital mechanics calculation, not a table you can memorize.

How to calculate the time with our calculator

The ISS Tracker homepage has a live pass calculator that does all this work for you in seconds. Tap "Sync Position" (or enter your city manually) and you'll instantly get the list of upcoming visible passes sorted by date, with exact time, maximum elevation, and direction — no install, no account needed.

It's the most direct way to answer "what time does the ISS pass today?" with an actionable number instead of a generic approximation.

If you also want tips on spotting the ISS in the sky, telling it apart from a plane, or photographing it, check our full observation guide, which complements this page.

Frequently asked questions

Why doesn't the ISS pass at the same time every day?

Because it combines a 90-93 minute orbit inclined 51.6° to the equator with Earth rotating beneath it. Every lap flies over a different strip of the planet, so the pass time over any given point shifts daily instead of repeating.

How many times a day does the ISS pass over?

It completes about 16 full orbits every 24 hours, so it technically flies over your area several times a day. But it's only visible when that overflight lines up with the twilight window where you're in darkness and it's still sunlit: usually 0 to 5 visible passes per night, depending on the season.

How long does a visible pass last?

Between 1 and 6 minutes, depending on the maximum elevation it reaches. Low passes are short and easy to lose behind obstacles; high or overhead passes can stretch several minutes with excellent visibility.

Is there a reliable app or website to calculate it?

Yes: this very page uses the ISS's official orbital data (TLE) to calculate the time, direction, and elevation of your next visible passes in real time. Just sync your position on the homepage.