2009 · ソースブック（プレイを拡張するルール／オプション）
Caelumancy
This d20/OGL supplement explores Caelumancy, the magic of creating permanent weather and environmental effects. It explains how spellcasters craft these effects as magical items, with 37 unique examples ranging from rain in deserts and snow in the tropics to devastating storms. The book also includes new feats for improving environmental magic and other magical crafting, rules for sentient effects, and sample locations for introducing Caelumancy into a campaign setting.
ダイス（主にd20）レベル制（XPを獲得してレベルアップ）属性／ステータス制（STR、CON、PERなど）
ゲーム情報（人数、プレイ時間、対象年齢、クレジット）の出典：BoardGameGeek。