There is this one author technique that I find a bit cliche, which is matching the mood to the setting. This means that for example, when one character is upset, the skies are grey to match the mood of the character. I wanted to add this technique to my story, but I don't want it to seem too cliche. Every time a character is upset, the skies are not always gloomy. How can I use this technique without making it too cliche?
The weather (or other elements of the setting) can have an effect on the characters, but the character's mood has no effect on the weather.
A gray, overcast day might pull your character's mood down but the depression your character feels can't make clouds appear.
Look at real life, for Pete's sake. Funerals happen on bright, sunny days and people get married when it is pouring rain outside.
Coincidences happen - sometimes funerals do take place on cold, rainy, nasty days. My wife and I got married (over twenty years ago) on a beautiful late summer day.
Making the weather always match the character's mood is just a bad idea, though. That stretches coincidence beyond belief and into cliché territory.
A funeral in October (in the northern hemisphere) can realistically be expected to take place on a nasty day. A funeral in mid-summer can reallistically be expected to take place on a sunny day - with maybe an afternoon thunderstorm.
The weather can contribute to the setting and the characters' mood. Bad weather can make a bad time seem worse.
Conversely, a bad mood can cause a character to perceive the weather as worse than it really is. If you are already feeling down, then a rainy afternoon that postpones a planned event can be a total bummer - it'll be perceived as a totally crappy day, when it really isn't.
Avoid the cliché, or subvert it.
Have a depressed character wonder how life can be so shitty on such a beautiful day - a funeral on a summer's day when other people are going to the beach.
Have a happy character note the contrast of their good mood with the grumpy people stomping through the rainy streets.
If you must make the setting fit the character's mood, try to make it believable. Make it look like the character's mood just coincidentally matches the setting rather than having the setting follow the character's mood.
Of course, a fantasy setting can turn that on its head. A fantasy story may well have a character whose mood really does influence the weather - but that needs to be a part of the story and the fantasy world.
The secret behind this is that we never perceive things neutrally, but always through the lens of our mood, our experiences, and our emotions. Coloring the descriptions can be powerful way to put the reader in the head of the POV character, and to make a more immersive experience.
With that said, your moods aren't actually affecting the weather unless you're some kind of demigod or nature spirit. So the key as a writer is not to change the setting to match the mood, but rather to change the way the setting is described. Here's a sunny day described by someone in a grim mood: "The sun was a merciless, reproachful eye, staring at me out of a pitilessly blue sky, one lacking the grace of even a single cloud." Now, here's a rainstorm described by someone in a great mood: "Electricity charged the air, and the rain hitting my skin made me feel invigorated and alive."
It's not the dull, factual details of the setting that convey the mood. It's the way the POV character experiences them.
This technique can feel cliché when it's used clumsily for effect rather than fitting the story.
In a solid, working story, everything should fit together seamlessly, the story, the characters, the setting, the dialogue, almost as if the reader is watching you piece together a puzzle right in front of their eyes and when they see the final picture, everything is just as it should be and creates a wonderful 'ahh' moment.
If you draw in a moody sky just because the character is gloomy, but it doesn't fit the rest of the story, it'll look wrong in the final picture and the reader will see that you shoehorned it in there for effect.
Whereas, if you read a story like Hills Like White Elephants, for example, the sadness of the female character isn't conveyed by a gloomy sky (that would have been cliché). Instead, Hemingway uses a bright sunny day. Even though the weather doesn't match her mood, the heat conveys the pressure the man is putting her under (there's no shade). The sun like a spotlight on her, hounding her to make a decision. And in the far distance - the future after she makes the decision - there's a single cloud.
Of course, Hemingway is a genius and less is always more when you're starting out. Better to tell a good story plainly, and then, when you have a feel for your story and know such techniques will add rather than detract, go back in a future draft and pepper them in carefully with a fine brush.
It's not always necessary to match the weather and general atmosphere to the mood of your main characters. In many books, scenes where the character is upset often are bright and sunny. The contrast effect gives you a lot of opportunities to talk about your character's feelings.
And it's also not wrong to have gloomy weather during sad scenes. Just make sure you focus more on your plot and story, and try not to lose the reader's attention with lengthy descriptions. It can get repetitive when you start talking about rain and grey skies.