Precipitation (spell)

Precipitation is a spell that conjures a light, steady rainfall within the area of effect. The rain falls at a rate of one eighth of an inch every 8 rounds, gradually increasing its impact on the environment over time. It takes just two rounds for stone surfaces and leaves to become recognisably wet, while the ground is distinctly wet with a thin sheen of mud after 12 rounds.

Precipitation

Range	10 ft. per level
Duration	4 rounds per level
Area of Effect	30 ft. circle, 120 ft. high
Casting Time	1 round
Saving Throw	none
Level	cleric (1st); druid (1st); mage (1st)

As the spell continues, the effects accumulate. Within the first few rounds, small flames such as candles flicker and are extinguished, starting with thin tapers and then progressing to larger, sturdier wicks. By the fourth round, delicate materials like thin cloth or paper become damp, while smooth, non-porous surfaces develop a slick wetness. As the rain persists, heavier fabrics like canvas and bundled twigs absorb moisture, becoming sodden after a short time.

By the twelfth round, water begins to collect on flat stone or metal surfaces, forming a thin, reflective sheen. As the sixteenth round approaches, torches succumb to the moisture and are snuffed out, while water runs in rivulets along smooth surfaces. Soon after, wooden surfaces become thoroughly soaked and exposed earth turns soft and spongy underfoot.

With prolonged rainfall, the spell starts to weaken fires, first affecting small flames after twenty-eight rounds, making them smoky and sluggish. By the fortieth round, water gathers in small streams along sloped ground, fully extinguishing small fires. Larger fires remain resistant at first but burn more sluggishly after sixty rounds, with thick plumes of smoke rising as embers struggle against the damp.

At thirty rounds, even large fires are doused, their flames fully extinguished — though deep coals and embers may still smoulder for another 5-10 rounds, requiring further soaking to be completely put out. Beyond this point, if the spell continues, the environment becomes thoroughly saturated, making dry shelter an increasing necessity.

Climate Effects

If the environment is already humid, such as in regions where the Köppen index indicates regular daily rainfall, the effects of the spell are doubled. Rainfall accumulates at a faster rate, soaking materials and extinguishing flames twice as quickly. Surfaces become slick twice as fast and fires succumb to the moisture in half the usual time. In these conditions, the spell creates a more immediate and pressing challenge for those seeking to keep dry or maintain a fire. Dry climates do not effect the spell.

In chilly conditions, where the temperature is just above freezing, the precipitation falls as sleet, creating an icy sheen on surfaces and making terrain treacherous. Wet surfaces become coated in slush and exposed objects rapidly develop a cold, slick layer of ice, affecting movement and visibility.

Snow Effects

If the temperature is below freezing, the spell produces snow instead of rain. The accumulation follows the same pattern, but instead of soaking surfaces, the snowfall gradually buries objects and terrain. Thin layers of snow accumulate on clothing and hair, while prolonged casting can create deep drifts that hinder movement and visibility. Fires are smothered rather than extinguished by moisture and exposed ground becomes difficult to traverse. In extreme cold, the steady accumulation of snowfall can present a significant obstacle to those caught in the open. This equals 3/16ths snowfall per round — effectively white out conditions with severe visibility reduction; if there is any wind blowing, combat would stop at once. It's then impossible to navigate without external guidance, such as a rope or a known landmark. The heavy accumulation would also make movement increasingly difficult, eventually causing persons to be immobilised.

Once the snow stops falling, however, the conditions likewise dissipate almost immediately. The primary cause of a white-out is active snowfall and wind reducing visibility, not the accumulation.