There is a long-standing international joke about English people always talking about the weather. When these jokers arrive on our shores, they realise why. We have one hell of a lot of weather. As a rather bemused U.S. student reported home one day, “you can have all four seasons in a single day here!” Hence why we talk about it. Rather like other countries talk about presidential elections. It can have a real effect on our lives.
Not always, of course. But often.
So, what’s the weather like in your fantasy world? Anne McCaffrey did a brilliant job of working the weather into her Dragonriders of Pern series. Omnivorous and voracious Thread falls at intervals, ruling the colonists’ lives and producing an entire sub-culture focussed solely on fighting Thread and protecting the rest of the population and their homes/farms. Although her books are more science fiction than fantasy, she does an excellent job of world-building. Although not the first to be published, Dragonsdawn deals with the arrival of humans on Pern and is well worth reading, for entertainment as much for worldbuilding.
Something to bear in mind with weather is that it does have a scientific basis and this is borne out by the science fiction nature of Anne McCaffrey’s novels. Therefore, if you want to give your world a weather system which literally produces downfalls of stair rods, you’re going to need to explain that at some point, possibly with a discussion on certain metals and other elements being present in the atmosphere and subsequent chemical reactions.
Likewise if you start writing about truly ‘acid’ rain. Apparently Venus would have this because its atmosphere contains a large amount of sulfuric acid. Under these circumstances you have to then work out how a ‘normal’ civilisation would function. How would you grow crops and raise animals?
Another example might be a world that experiences heavy rain every night and searing sun every day; plants might spring up in the night hours and then wither away in the daytime – what would this mean for the people living there?
All these situations will require one of two paths. The first possibility is a civilisation with a system for protection from the elements. A natural progression is that exclusion from the system would be tantamount to a death sentence unless another protected location can be found. Therefore more than one civilisation would arise and the two could well be in conflict with each other. Since the first civilisation would have most of the technology and benefits and the others just what the first discarded, these ‘lesser’ civilisations would have motivation for attacking the first. This is a basic storyline that has been seen before but bears considering.
Alternatively, your world’s residents could evolve to handle the weather conditions. Wild animals, for example, will have to deal with whatever you throw around in the way of weather without any artificial protection, just as the people will. What you do to your entire world affects everyone on it, regardless of species. The weather would be an evolutionary factor and could lead you to develop some very awesome species, such as people evolving a large bony carapace over their heads, like a parasol, that deflects falling stair rods. Or heavily alkaline skin which neutralises acid on contact (providing drinking water?).
Isn’t world building fun?!