Of course, from my viewpoints, that's true of a lot more than the weather. But I have a simple solution: for just about anything -- temperature, rainfall, wind force, wave force -- there are exactly three levels relevant to playing an RPG:
- real effect.
The fluff level is just description to make the scene seem real; you don't emphasize fluff details. A warning is also just description, with no mechanical result, but it hints that things are changing and the players might want to prepare. A real effect actually does something, possibly causing damage, slowing movement, or some other... real effect.
Let's use sea waves as an example. Here's fluff: "Waves lap at the side of your boat as you row out to the island." There's no reason for the players to be worried, although if they get overly nervous, that's always fun. Here's a warning: "As you pull the boat ashore, you notice that the waves appear to be getting rough." This lets the players know that the sea conditions may be changing for the worse; they might want to keep their time on the island short, or prepare shelter now in case they have to wait out a storm. And here's a real effect: "When you return to the row boat, you see that the sea has gotten very turbulent and the waves are high. They look like they could capsize your small boat." This is you letting the players know that there will be dice rolls coming up if they brave the rough waters.
Wind is the same: "There's a soft breeze as you cross the meadow" (fluff) vs. "The wind appears to be picking up" (warning) vs. "The winds are battering you about, making it difficult to remain standing" (real effect.) It can be used for dying winds, too, if that is relevant, such as when sailing ("The wind appears to be dying down as the skies clear" vs. "Everything is dead calm, and your sails hang limply from from the mast.") Some things, like temperature, have two extremes (hot and cold;) you can apply three levels to either extreme.
And you can apply three levels to anything, not just weather. Insects: "The meadow is buzzing with flies and other insects" (fluff,) "You hear an ominous buzz that appears to be getting louder" (warning,) and "You see a large, black swarm of flying insects approaching!" Terrain: "The floor is covered with pebbles" (fluff,) "The slope becomes steeper, and the loose gravel is making you nervous" (warning,) "The tunnel ahead is steeper; it looks like it will be tricky to keep your footing."
You can, of course, have various degrees of real effects, with each degree being a warning for the next one. You can also substitute "clues" for warnings, if the real effect is useful or even beneficial.