There's a cool tool you can use to find the random seed that generated your island.
Useful as it basically predicts the weather for you forever, including star showers with exact times for each falling star even!
You just enter data and it eventually finds your seed by searching all 2 billion seeds for one that matches your data.
https://wuffs.org/acnh/weather/
Mine is 514360667 (posting it just so I don't lose it)
You can enter in general weather, but that would probably take a while. They suggest going through screen shots to get more data.
Or I found I had a star shower tonight, I found trying to get the exact second was difficult as my PC and switch clock aren't totally synced, so I just entered in the minutes that had a falling star in it. I tried entering the gaps but that started resulting in no seeds being found so I removed those unless there was a gap of 2 minutes so I could put one minute on one side and another on the other.
After about half an hour of that it had enough data to give me one seed. Then I checked and it perfectly predicted the exact second each falling star fell.
Pretty neat, helps with making sure I get a few of the zodiac fragments each month.