How careless to have opened yourself up with such absolutes as “On the question of how reliable the figures are, the amazing truth is that they are absolutely 100 percent reliable all the time”. Not to be nitpicky, but I’m a nitpick. The historical data will be accurate, in reference to history. But as far as reliability goes for “today”, always is definitely wrong. For any day under the current conditions where it either has rained 0% of the time, or 100% of the time, you could see a first. The first time you either get rain, or don’t get rain, under “today’s” historic conditions, the prediction will be incorrect, hence not always reliable.