Liked the idea mentioned by orian34 earlier (fresh to this forum, so I sadly don't know how to add quote's properly) about lunar event "weathers". I can imagine these events happening very rarely after you defeat plantera (or maybe after one of your first solar eclipses/hardmode invasions) with relevant mob spawns and appropriate graphics to boot. After the cultists and pillars have been dealt with the first time, and the following defeat of the moonlord, these events would become more common but still rare (Reason? The energy of the pillars maybe attracted similar energies/enemies from other parts of space, making the events more commonplace). Even though they would not be "weather", I could still imagine them counting as weather due to the fact that it's the energies of the pillars that cause these events over time. Like the solar energy causing hot winds and flares, starlight causing a coldspell, nebula causing maybe acidic and status effecting rain, and the vortex causes dreadful lightningstorms.
I thus present the following names and effects (Feel free to change anything here):
Solar wind: Enemies from the solar pillar event would start spawning everywhere, and drop appropriate loot for that invasion type, albeit not at the same rate as to prevent this event from becoming OP (and make pillar farming redundant). The background would take upon the same colour scheme and have meteors falling, but one would also see the sun flaring up stronger than before (during the day), and the moon would become brighter and change colour to a more orange tint. One would also see auroras (different colours than in snow biome) even in biomes outside the taiga, and during the day the sky would have a similar wavy effect like one see's in deserts, as to point out the "heat" nature of the event. A status effect called sunburnt/scorched could also affect you, causing you to take more fire damage than normal (add other effects here).
Space storm (vortex): Same setup as before, but instead of a flaring sun, one would see a large amount of lightning happening in the sky and in the space above the clouds (in the space background). The colour spectrum would be the same with the night sky having a green tinge as a cosmic storm passes over the planet. Lightning strikes are more common during this event, and you get a status effect called energized that increases all types of speed, but increases mana consumption/usage (distruptive energies in the sky) and potion cooldown (not sure with the effects on this one, feel free to change).
Nebulous clouds: Same deal. This event would pour down with a strange "purple rain" (
) that upon contact can cause the player to gain a lot of different status effects. To avoid the worst of them (makes the ones later in the game more rare) an ankh shield or something similar is a must before you brave this weather event. The background would have this purple haze with strange flashes in the fog (maybe even shadows of the event enemies), and higher up in space you would see this bright nebula full of stars, hanging over the entire world. The status effect of the rain can be called "Nebulous miasma/sludge", and would basically work like an upgraded version of feral bite.
Arctic starlight: Same. The event would feature completely clear skies (not a cloud in sight), as to reflect the coldest nights one can experience in one's respective country. The stars would be particulary bright in sky (that has the stardust blue tinge), and blink more pronounced than before (as to reflect their effect on the world). You would be really cold, and under the status effect "astral freeze". This effect would essentially make you a glass cannon, increasing your damage output at the cost of cutting down defence (maybe even lower or cancel natural regeneration). The change to the skybox (space area) would be the brighter stars and maybe comets of frozen material passing the planet (like blue comets or clumps of ice passing by in the background).
These are my ideas on the matter at least. Made on a relatively short notice. As for other events (I'll be more short here), I could really see some mod inspired weather types as well. Here's a short example for Calamity:
Brimfire storm: Brimfire (ex. calamitas projectiles) rain down from the sky for a short time, and the skies turn a deep crimson red. Will serve as a homage to what Calamitas did to the ancient ocean that is now the large desert above the sunken sea, just in a smaller form.
These are my thoughts on the matter. Sorry if this was a bit massive, but I feel that the idea of pillar inspired weather really needed fleshing out. And the fact that I'm absolutely in love with this mod does not help the matter either. If there are others that have had similar ideas that I have not included here (quoted), I'm sorry in advance and will change my post if necessary. I would also see the need to have a deployable item (like a shield) that prevents your home base from suffering the effects of these events, for the safety of yourself and all the NPC's.
