Modify Climate

9th level transmutation (cleric, druid, wizard)

• Casting Time: 8 hours
• Range: Touch
• Components: V, S, M (an orb of obsidian worth at least 5,000 gp, which the spell consumes)
• Duration: 1 year

By infusing an obsidian orb with powerful atmospheric magic, you influence the climate of the region around the orb for the duration. The region can be a minimum of a 1 mile radius around the orb, and a maximum of a 25 mile radius. Choose one of the following ways you want the weather to be influenced.

Colder. On each day for the duration, the temperature is (1d6 - 1) × 10 degrees Fahrenheit colder than it would normally be on that day without magical influence.

Warmer. On each day for the duration, the temperature is (1d6 - 1) × 10 degrees Fahrenheit warmer than it would normally be on that day without magical influence.

Drier. On each day for the duration, the state of precipitation is shifted 1d4 - 1 stages upward on the Precipitation table from where it would normally be on that day without magical influence.

Wetter. On each day for the duration, the state of precipitation is shifted 1d4 - 1 stages downward on the Precipitation table from where it would normally be on that day without magical influence.

Calmer. On each day for the duration, the wind will be (1d4 - 1) × 10 miles per hour weaker than it would normally be on that day without magical influence.

Windier. On each day for the duration, the wind will be (1d4 - 1) × 10 miles per hour stronger than it would normally be on that day without magical influence. You can also choose the most common direction of the wind. At the start of each day, the DM rolls a d20. On an 11 or higher, the wind will be blowing in the direction you specified.

Fewer Storms. Whenever a non-magical storm, such as a heavy rainstorm, thunderstorm, snowstorm, or windstorm, would enter or form in the area, the DM rolls a d20. On an 11 or higher, the storm dissipates or fails to form, and the region experiences a calmer version of that weather instead, such as light rain for a dissipated thunderstorm, or a slightly windy day for a dissipated windstorm.

More Storms. On each day of the duration that would not normally have a storm, the DM rolls a d20. On an 18 or higher, a violent storm such as a heavy rainstorm, a thunderstorm, a snowstorm, or a windstorm breaks out on that day. The nature of the storm will be appropriate for the region and is determined by the DM.

The climate controlling magic will be kept within the obsidian orb, which is affixed to the spot where you cast the spell by magical force similar to what powers an immovable rod. The orb has 20 hit points and an AC of 15, and can be moved from its spot with a DC 30 strength check. If the orb is destroyed or moved, the spell ends, and the weather gradually returns to normal. Dispel magic can only end this spell if it is cast directly onto the obsidian orb.

Once the spell is cast, the changes will take hold gradually over 24 hours. You can end the spell as an action if you are within the area being affected by it. All rolls to affect the weather happen at dawn each day. If you are within 5 feet of the orb at dawn, any die that is rolled to influence the weather is rolled twice, and you can choose which of the two numbers to use.

Multiple instances of this spell that influence the climate in different ways can affect the same region. For example, if one casting makes the region colder and one makes it wetter, the region will be both colder and wetter than average. If two instances of this spell on a region have the same type of influence, the climate will be affected as if there were only one instance. If two instances of this spell directly contradict each other, such as one that makes the region warmer and one that makes it colder, the magic cancels each other out and the region is unaffected by both.