I'm gonna be asked about Predict Weather, I think. Today's base expectation is ye olde' 10-Day Forecast, available damn near everywhere.

So, with some light Googling:

Predict Weather gives you the next 12 hours in a 1 mile/level radius, accurately.

Internet tells me that, generally, next-day forecasts are ~95% accurate, for temperature at least.

Divination, if used on something so boring as the weather, gives us a 60% + 1%/level base chance for a correct answer.

Internet tells me that 5-day forecasts might be something like 77% accurate, so 5 day forecasting technology is a pretty high level diviner.

Doubling that drop, I might pretend that 10-day forecasts would be ~30% accurate.

So...I'll pick a fortnight, 14 days, as the max range, as that fits nicely with max level. I'll end it at ~5% chance at 14 days for the 1st level caster, being the equiv. of a natural 20. If I take those points and apply a bit of a modified quadratic fitting:

Rounded % | Base % | Days Out | @7th | @14th |

97% | 97.20% | 1 | 104% | 111% |

91% | 90.93% | 2 | 98% | 105% |

85% | 84.52% | 3 | 92% | 99% |

78% | 77.96% | 4 | 85% | 92% |

71% | 71.27% | 5 | 78% | 85% |

64% | 64.44% | 6 | 71% | 78% |

57% | 57.47% | 7 | 64% | 71% |

50% | 50.36% | 8 | 57% | 64% |

43% | 43.12% | 9 | 50% | 57% |

36% | 35.73% | 10 | 43% | 50% |

28% | 28.20% | 11 | 35% | 42% |

21% | 20.54% | 12 | 28% | 35% |

13% | 12.74% | 13 | 20% | 27% |

5% | 4.80% | 14 | 12% | 19% |

we may or may not have something that could approximate today's weather prediction technology, which may be indistinguishable from magic.

No idea what level that'd be - a limited range divination that can only ask about 1 particular unavoidable, and unchangeable, thing?