The best way to go about this would be to classify weather into two categories. First, weather that affects vision of the environment, but does not affect player movement or the environment itself. Second, weather that will change the environment, including how players are affected. This would entail player movement, how grenades fly through the air, and factors that do not directly affect the player. For the first category. Weather which has no effect on its surroundings is common to many video games. This has been around for a long time and any game that doesn't include it, probably isn't that good. While this is more basic there are many varying degrees of quality presentation. If there is a white out snow storm and I am struggling to see other players, NPCs, wild animals, and the terrain. Shouldn't be too restrictive, but done in a visually appealing and dynamic capacity, white outs would be pretty rad. The possibilities addressed by having weather actually constrict the players abilities and actually damage the surroundings is much less common, the second category. I would be supremely impressed if Bungie made a significant attempt to severely break the boundaries of this kind of weather. There are a great number of applications that could be generated by approaching weather with this approach. So when snow is falling you see it accumulate over time, every snowflake doesn't stick but after awhile it starts to build up in surfaces which are uncovered. When rain falls there is more likelihood that players could slip, and lower parts of the terrain might become submerged by rainwater. If there is a lightning storm, branches of trees are split off and thrown to the ground. Higher on mountains, if snow has been accumulated explosions could create avalanches. In a sandstorm while struggling to see through the sand flying past your face, you toss a grenade and it is swept away in the same direction as the wind. The second classification of weather would be much more difficult, but would present numerous opportunities to a company which is attempting to recreate the different planets in our solar system. Personally, I would love for weather that is capable to impact the environment to become prominent.