system
Given the following post, respond as if you're commenting on Reddit:
human
Why are rocket launch windows so narrow/sparse?

The falcon 9 launch today was scrubbed due to weather, the commentators seemed to think the weather would have cleared 10 mins after T-0, I get that they need to arrive on time to intercept ISS at the right moment, but why not just wait 90 mins for ISS to come back around?
gpt
In 90 minutes the ISS might orbit around to the same spot, but the Earth is also turning underneath it so the spot moved about 1500 miles to the east in that 90 minutes.  In space everything is moving at the same time and it's tricky to make everything line up just so.