How it works
The International Space Station circles Earth about every 90 minutes. You can see it only when your sky is dark but the station, about 250 miles (400 km) up, is still in sunlight. That usually happens for an hour or two after sunset or before sunrise.
The tool downloads the station’s latest orbit from CelesTrak and works out its position every 20 seconds for the next week. It lists passes that climb more than 10° above the horizon while the station is sunlit and your sky is dark.
Passes higher than about 40° are the brightest and easiest, and they are highlighted. The ISS looks like a bright, steady star moving smoothly across the sky with no blinking lights. A pass can end suddenly in mid-sky when the station enters Earth’s shadow.
The orbit changes slightly after engine burns, so check again on the day. Times are estimates to within about a minute.
Everything is calculated in your browser. Your location is used only on this page and is never sent to us. ISS orbit data: CelesTrak, updated several times a day. Calculations: satellite.js (MIT license).
The International Space StationA football-field-sized lab in orbit, crewed since 2000 and easy to spot at dusk.
Satellites in the night skyHow to spot the ISS, Starlink trains and other satellites, and how they affect astronomy.
Gravity and orbitsWhy planets circle the Sun, why the Moon never falls, and what keeps JWST in place.