Hi there

There is some science involved - it's called the solunar theory.

Some sites don't include daylight savings in their predictions and leave it up to users to add or take off an hour.
Others use general locations and therefore don't have the correct moonrise, sunrise and timezone data for a specific location.
The day rating may also differ. Here on fishingreminder for example we include the maori fishing calendar to determine dayratings. Others might only rely on moon data only.

The main factor for calculating the fishing times is the moon and sun.
If the moonrise and sunrise is correctly displayed, then most likely the fishing times predictions for major and minor times will be correct.

But having said that - there is always a possibility of bugs in software.
If you find any major discrepancies like wrong sunrise/moonrise etc - then let us know so that we can investigate for possible errors.

Cheers and tight lines