Rain: A Dungeon Master's Tool for Storytelling
Weather is a powerful, world-impacting event that is out of the characters’ control. This makes it a useful tool for Dungeon Masters (we call them Quest Masters) to control story progression, introduce powerful and flexible mechanics to adjust combat difficulty, and introduce vivid depictions of the settings.
Quest Masters (QMs) can utilize rain to affect the rate and direction of story progression. By extending the duration of a rainstorm, the QM can keep characters in a key location until all of the objectives have been completed.
For instance, if characters fail to locate a secret door to a library, which holds a clue to the location of the campaign’s MacGuffin, the QM may introduce a rainstorm which forces characters to linger longer inside the house. Hopefully, they will stumble across the secret entrance while waiting out the storm, as they have not much left to do besides investigate.
Rain can be used in a similar manner to encourage characters to talk with NPCs or to keep them in a key location until a time-sensitive event unfolds. Similarly, a heavy rainstorm may be used to prevent characters from visiting unnecessary locations or straying further from the plot. If characters are forced to linger in a location before moving on, you can use the time to introduce new plot hooks or add details which would discourage them from visiting the unwanted location.
Alternatively, if enough out-of-game time passes, the players may forget their plan to visit the location and move onto a more relevant part of the plot. Delaying advancement of characters in-game can also give you more time to prepare out-of-game for the location if you have not read ahead or fully fleshed out the location in question.
Rain can be used to create mechanical advantages (or disadvantages) which enhance the game-play experience. If characters have a random encounter which would be too easy, a rainstorm can be added to increase the difficulty. A downpour could create disadvantage on ranged attack rolls, making monsters more difficult to hit. Puddles and rivulets of water can create difficult terrain, decreasing the characters’ mobility.
Rainstorms can potentially increase the potency of certain enemies, such as druids who can cast Call Lightning or Water Elementals. Heavy rain may decrease visibility, imposing disadvantage on Perception checks and advantage on Stealth checks, allowing stealthy enemies to easily hide from characters or set an ambush, resulting in a Surprise Round.
For example, a group of Drow mercenaries could use the cover of night and an unseasonable rainstorm to creep across rooftops, slowly closing in on the characters as they pass through an abandoned alley. Imagine a mercenary silently slipping to the ground, the sound of the falling rain disguising her footsteps. As she sneaks behind the party’s paladin, she is able to slide a blade across his neck before the party even notices her presence.
These same tactics may also be used to the advantage of players, increasing the Stealth of PC rogues, adding to the potency of allied Call Lightning spells, and causing enemy ranged attacks to be made at disadvantage. All the while, friendly PCs can close the distance between the party and enemy combatants more safely.
Heavy rain has the ability to change the terrain of an area, introducing monsters which are not typically found in the location. For instance, a storm drain may flood into a city street, allowing trapped Giant Crocodiles to emerge. Pools of water in the road may act as portals to the Elemental Plane of Water, allowing monsters and characters to pass between the planes. Or a dam may overflow and release a lake monster, such as a Hydra, into the river below, which decimates coastal cities and towns as it makes its way towards the ocean.
Rain introduces stunning imagery which can enhance certain scenes and settings. A shimmering summer storm may highlight the glinting scales of a young gold dragon flying over the walls of Waterdeep. The gentle fall of rain can accentuate the appearance of an otherworldly creature, arriving to aid the characters in their quest. Or a sudden moment of calm in an unforgiving rainstorm can represent a character’s moment of clarity or a powerful god’s answer to a character’s desperate prayer for assistance.
Narrated correctly, rain can stir up feelings od discomfort, stress, and uncertainty. A heavy downpour can reduce visibility, where enemies appear to move out of the corner of the character’s eye just to disappear in the deluge. The sound of falling rain may mask the movement of enemies, creating an echoing thunder within the walls of a crumbling cathedral. Or rain dripping off the maws of raging monsters or the rotting flesh of zombies can create vivid and memorable imagery for characters to interact with.
By including rain and other weather events in the descriptions of events, you create a more involved and realistic world for characters to interact with. This forms an immersive experience for players, allowing the world to be shaped in their imaginations and create vivid, memorable, role-playing experiences.