Precipitation

Precipitation is a phenomenon that occurs as a part of normal weather changes. This feature is introduced in The Sims 2: Seasons. Unlike the real world, precipitation in the Sims' universe is essentially a random event; while Sims can get weather forecasts by reading the newspaper or watching the weather station on TV, they are not notably useful for predicting precipitation. There are three kinds of natural precipitation (rain, hail, and snow), and an artificial one (rain of fire). Each of the natural precipitation types may occur early in the following or preceding season, not only the current one. Thus, heavy snow may occur on the first day of Spring if Winter was just over, and a heavy snowfall occurring when Winter changes to Spring will continue. Of course, it will not snow in the middle of the Summer.

Precipitation can be described by its type, intensity, accumulation, and duration. All of these depend on the season. The type, as described above, is the kind of precipitation, whether it's rain, hail, or snow. The intensity determines how heavy the precipitation is. For example, hail may or may not be heavy enough to damage crops and injure Sims, snow may occur in light flurries or in a heavy snowfall that eventually covers the ground, and rain may fall in showers or in a thunderstorm. The duration is random.

Each season also brings different chances of daily precipitation:
 * Spring: 30% daily chance
 * Summer: 20% daily chance
 * Fall: 15% daily chance
 * Winter: 50% daily chance

Additionally, precipitation will neither occur nor stop if Tempus Interruptus spell is cast by a Witch. Precipitation, as well as the current season, can be controlled by the Weathernaught 57X Aspiration reward. Some Sims usually want or fear to see certain precipitation types.

Rain
Rain occurs in almost all seasons, except Winter. It most likely occurs in Spring. Rain has several effects on gameplay. Rainfall waters the flowers, plants, and crops; light rain may not cause overwatering, while heavier rains or long rain causes greater effects that may overwater the plants. Rainfall extinguishes outdoor fires.
 * Seasons: Spring (30%), Summer (10%), Fall (15%)
 * Intensities: Light, heavy, torrential
 * Accumulation Levels: Puddles

Sims are more likely to do indoor activities while it is raining. Rain also satisfies a PlantSim’s Water need and revives Sims who suffer from heatstroke. Servos are rain-resistant, though they can get short-circuited when splashing in the puddles. Cats don’t seem to be afraid of rain. Rain can be made by Evil Witches’ spell Corruptus Locus, while it can be stopped by Good Witches’ spell Beautificus Locus.

Rain never stops in the Fortress of Eternal Darkness.

Rain Puddles
Rain puddles begin to appear after it’s raining for a while. This kind of puddle is different from the regular one. Sims can splash in the puddles to raise fun. They can also mop them up, though that is not necessary because outdoor rain puddles will evaporate after the rain has stopped. Indoor rain puddles still need to be mopped.

Rain puddles and original puddles can be easily distinguished by their colors; rain puddles are paler. Rain puddles will not mix with other puddles even if they're adjacent to each other. Only rain puddles can evaporate.

How quick the rain puddles form depends on the intensity of the rain. Thus, the heavier the rain is, the faster rain puddles appear.

Lightning
Any rainfall can include lightning, but the more intense it is, the greater the chance. There are two kinds of lightning strikes, essentially:
 * Distant Strike. This lightning strikes beyond the lot. It causes thunder, and sometimes causes a flash, but does not affect the current lot. The apparent distance from the lot may vary.
 * Local Strike. Local lightning strikes something in the lot, either objects or Sims. An actual lightning bolt can be seen striking in the lot, in addition to a big flash in the sky and heavy thunder sound.

Local lightning strikes can be dangerous, causing fire, mayhem, and even death. Lightning strikes random objects, but some objects are more likely to get struck.
 * Trees. Most trees other than orchard trees can get struck by lightning.
 * Lightning Rod. The EZ120v Lightning Finial is a functional roof object, that can be used as a decoration and a lightning strike prevention. Unlike real-world lightning rods, it is also effective if placed on the ground.
 * Large Objects. The larger the object, the more likely it is to get hit.
 * Pools and Hot Tubs. Sims who are in a pool or hot tub are the frequent targets of lightning strikes. The difference is, only one Sim gets struck in the hot tub, while all Sims in the same pool get electrocuted.

Most of the time, fires caused by lightning strikes are extinguished immediately by the rainfall, but in rare situations, the rain stops after the very last lightning strike. In this situation, the fire won't be extinguished. If this happens to a tree, the fire cannot be extinguished, but may disappear if the player saves, exits and reloads the lot. (This appears to be a case of the FX being stuck, rather than the fire itself persisting.)

The Sims Castaway Stories
Rain also appears as a feature in The Sims Castaway Stories. Rain will significantly lower Sims' temperature. In addition, it will put out fire, and fire cannot be made until the rain is over.

Hail
Summer is the only season in which hail occurs. Hail can be light or heavy, and heavy hail can be deadly. When heavy hail falls, Sims react by covering their heads. Light hail doesn't impact Sims' motives, while heavy hail will drain their motives quickly. There is a random chance that, in heavy hail, a hail barrage will fall from the sky and bludgeon Sims outside. Sims who get bludgeoned by this hail barrage will experience a sudden drop in their needs, and, if their needs are low enough, will die. Hail can also damage crops by lowering the quality over time.
 * Seasons: Summer (10%)
 * Intensities: Light and heavy
 * Accumulation Levels: Hail on Ground

Hail tends to be briefer than other forms of precipitation, but heavy hail may last long enough to accumulate on the ground and on roofs, though it will not build up as snow does. However, unlike real-world hail, even heavy hail will not damage objects that are outdoors.

Snow
Snow is primarily a Winter event, though some days in Spring and Fall may get cold enough for brief snow flurries to occur. There are few differences between light and heavy snow, other than how quickly snow will pile up on the ground. There are many activities that can be done in snow, but most activities are only available in heavy accumulation. However, playing in snow will lower Sims' temperature quickly. If they are wearing outerwear, it will still drop, but not as quickly. Snow also attracts penguins. Snow on the ground will eventually melt if no more snow falls. Melting snow will leave puddles which behave like rain puddles.
 * Seasons: Winter (50%)
 * Intensities: Light and heavy
 * Accumulation Levels: Snow on Ground

Snow Activities
These activities can mostly be done if there is heavy snow accumulation.
 * Sims can have snowball fights with others. This is similar to having water balloon fights.
 * Sims can build snowmen alone or together. Snowmen, partial or finished, attract penguins.
 * Sims can create snow angels on the ground.
 * If heavy snow falls until morning, there is a chance that school will be canceled for a snow day. Children and Teens react to it according to their personality (Cheer/Sigh).
 * Toddlers can play in snow.
 * Toddlers and dogs can eat snow.
 * Some interactions are disabled outdoors, i.e. Hanging Out, Stargazing, Working Out, Yoga, and Jumping Rope.
 * Snow can damage the quality of crops.