"The biggest part of being a weather forecaster is looking at the sky. It's everywhere, providing everywhere actually means 'up'. And, if the preceeding sentence resolves as true, you will have found the sky. Well done. You've just experienced photo-tropism. Feeling drowsy yet?
The sky, named by the Ancient Greeks after the God Of Television, is a very long way away. Further, in fact, than the distance you would get if you placed all the World's trains end to end in a vaguely upwards direction. That process, while in itself being a bit tricky to pull off, would only get you just under half way there, mainly because the sky is, to be scientific about it, fucking far off.
Early star gazers considered the sky to be "about as far as Milan," before keener types such as Galileo, Scaramouche, Bizmillah and Moore et al demonstrated this to be untrue, causing the early mob to quit astronomy and take up jobs as information clerks for Italia Railways, at which they were very successful until some idiot stole all the trains in the name of 'scientific research'. When telescopes got larger, mankind gained taller buildings to put them in, resulting in the contents of the sky getting somewhat closer than they were before, though still not as near as Milan.
As time travel becomes more widespread, everyday humans will be able to see the wonder of the sky without leaving the kitchen. Only then will the true distance to the sky, and, presumably, the heavens (for a long time believed to be a mere three steps away), be accurately known. We'll be able to look at what the sky looked like yesterday, last month, before Christ, tomorrow, next week - all with the accuracy of having been there. Want to know what clothes to take on your summer holiday to Lyme Regis? Simply strap yourself in to the RonCo Time Chair™, set the controls to Dorset, mid-June, and hey presto, all the proof you'll ever need to convince you to pack the chunky-knit jumper and wellies.
Here in the present, mankind has mastered the skies through technological breakthroughs to rival that of the slicing of bread. Satellites 'ping' data into dustbin lids nailed to the sides of houses in the blink of an eye, while inter-planetary probes can tell us the weather on other worlds. We can even land a souped-up vacuum cleaner on an orbiting comet with cocky nonchalance, yet forecasting the weather here on Planet Earth is still a three-A-Levels-and-a-mate-in-personnel sort of position to hold. Ultimately, it's not what you know, but what you don't.
Which is just as well, because this elongated spell of rain is making a tough job out of filling this page every month. Holy Nimbostratus Batman, this place needs a heatwave or something."