Control Weather (spell)

Allows the cleric to change the conditions and wind force of the locality, depending upon the previous conditions. This effect will cover an area equal to seven 2-mile hexes, or one 6-mile hex. At the edge of the adjustment will be a distinct, observable barrier about 20 yards thick, that anyone can pass through.

Control Weather

Range	self
Duration	4-48 hours
Area of Effect	3⅓ mile radius
Casting Time	3 rounds
Saving Throw	none
Level	cleric (7th); druid (7th)

The transformation caused will be striking, particularly as those encountering the barrier will likely have no awareness of the caster's involvement or any understanding of the phenomenon’s origins. Despite its unusual nature, the spell ensures that individuals below 5th level will be unable to give it significant attention, while only those of 10th level or higher will perceive it as something warranting investigation.

To cast this spell effectively, the caster must identify changes to the ambient temperature, wind force, and weather conditions.

Change in Temperature

The Temperature Grades table provides a reference for translating descriptive temperature terms into degrees Celsius or Fahrenheit. These descriptions exist because no standardised temperature scale is available within the 17th-century game world. The caster can alter the relative temperature by no more than two grades, either raising or lowering it. For instance, a "baking" temperature could be reduced to "sweltering," or "sweltering" could be lowered further to "balmy."

Temperature

Grade	°C	°F
polar	-40 or less	-40 or less
arctic	-35 to -39	-30 to -39
bitterly cold	-29 to -34	-20 to -29
very cold	-24 to -28	-10 to -19
cold	-18 to -23	0 to -9
wintry	-12 to -17	1 to 9
icy	-7 to -11	10 to 19
frosty	-2 to -6	20 to 29
chilly	-1 to 4	30 to 39
brisk	5 to 9	40 to 49
cool	10 to 15	50 to 59
pleasant	16 to 21	60 to 69
warm	22 to 26	70 to 79
balmy	27 to 32	80 to 89
sweaty	33 to 37	90 to 99
sweltering	38 to 43	100 to 109
feverish	44 to 48	110 to 119
baking	49 to 54	120 to 129
scorching	55 or more	130 or more

An adjustment of 12 to 20 degrees Fahrenheit can dramatically affect a character's comfort level. The dungeon master can enhance the atmosphere by describing sensory details, such as how characters experience the shift in temperature as the spell takes effect.

The temperature change takes 10 to 40 rounds (10d4), equating to 2 to 8 minutes of game time. As the adjustment occurs, characters wearing inappropriate clothing for the new temperature will need to adapt their CLO progressively, especially if the change happens during combat. For example, a reduction from "sweltering" to "cool" might prompt characters to don cloaks or seek warmth, while a shift upward could require the removal of heavy garments. Additionally, changes in temperature will visibly impact the environment. If the shift moves the surrounding weather from below freezing to above, ice will begin to melt. The surface of free-standing ice will become slick with water within 4 to 10 rounds, softening and altering its texture and hardness as it warms.

After the temperature adjustment is complete, the caster must decide what type of weather conditions are desired, shaping wind patterns, precipitation or other effects in alignment with the new temperature.

Conditions

Atmospheric Conditions

Grades	possible conditions
polar to icy	blizzard, clear, cloudy, flakes (very light snow), flurries, low clouds (100 ft. ceiling), overcast
frosty or chilly	clear, cloudy, flakes, flurries, fog (light to heavy), ice storm, low clouds, mist (freezing or chill), overcast, sleet
brisk or cool	clear, cloudy, drizzle, fog (light), low clouds, overcast, showers
pleasant to sweltering	clear, cloudy, overcast, showers, sunny, threatening clouds, thunderstorm (and hurricane in special conditions)
feverish to scorching	clear, cloudy, overcast, showers, sunny

Within the parameters set by the Atmospheric Conditions Table, the caster can define cloud cover, the intensity of precipitation, and the specific form that precipitation takes. For instance, if the temperature is classified as "brisk" or "cool," the caster may choose from seven weather conditions appropriate to that temperature range, such as "clear," "overcast" or "showers." The chosen weather must align with the established limitations of the temperature grade; for example, a hurricane cannot occur in "polar" conditions.

While extreme weather phenomena like hurricane-force winds might exist within certain conditions, such as a blizzard, the event would still adhere to the characteristics of the selected weather type — in this case, heavy snow and low visibility rather than tropical rains. This ensures that the atmospheric changes remain consistent with the natural laws of the game world, even as they are influenced by the caster's power.

Details regarding these conditions are explained on these links: Clear & Sunny — Cloudy & Overcast — Fog & Mist — Ice Storm — Rain — Snow — Storms.

"Storms" inherently involve significant wind activity. If the wind is minimal or absent, precipitation will simply fall as "rain" or "snow," depending on the temperature and atmospheric conditions. An "ice storm," for example, is not a traditional storm but rather a condition where freezing precipitation coats surfaces with ice, often occurring with little wind.

Hurricanes are exceptional and can only be created under specific meteorological conditions. The spell cannot generate a hurricane near land, as the atmospheric pressure and other factors required for hurricane formation are insufficient close to shore. Instead, hurricanes must be formed over the open ocean within the Tropics of Cancer or Capricorn, where the water temperature is warm enough to sustain the pressure dynamics needed for their creation.

Within these constraints, the caster may produce a small hurricane that lasts only for the duration of the spell. Upon the spell’s end, the hurricane will naturally dissipate. This phenomenon adheres to the principles of meteorology while allowing for limited control within the bounds of the spell.

Wind Force

Wind Force

Conditions	Wind Force min/max
blizzard	7 to 11
clear	0 to 6
cloudy	0 to 5
drizzle	0 to 3
flakes	0 to 3
flurries	3 to 6
fog (light)	0 to 1
fog (moderate/heavy)	0
hurricane	12
ice storm	0 to 1
low clouds	0 to 1
mist (chill)	0 to 2
mist (freezing)	1 to 2
overcast	3 to 6
showers	2 to 7
sleet	3 to 6
sunny	0 to 2
threatening clouds	5 to 10
thunderstorm	6 to 11

Knowing the conditions, the caster can now select the wind force desired. The diagram provides context beyond what the wind speed can provide. The smaller the number chosen, the calmer and more charming the weather will be. Forces 0-2 are considered "nice" weather, being still or airy. Forces 3 to 5 are "breezy," being lovely and enjoyable for a walk or to lay outside. Forces 6 to 7 are blustery, with large branches or whole trees in motion, making it difficult to walk. Damage to property begins with Force 8, a "gale;" Force 10 will uproot trees; Force 11 will tear away roofs; and Force 12 is a hurricane.

Any significant alteration to the wind force of 4 degrees or more will produce either an unnatural calm or sudden appearance in wind. If this is done during a combat, then everyone in the battle must make a panic check immediately.

Those who fail will break and retreat until rallied.