You create a 20-foot-radius sphere of fog centered on a point within range. The sphere spreads around corners, and its area is heavily obscured. It lasts for the duration or until a wind of moderate or greater speed (at least 10 miles per hour) disperses it.
You cast the spell; thick, swirling fog blankets a 20-foot radius area. The mist curls around corners, enveloping the space in dense obscurity, limiting visibility and muffling sounds until a strong wind disperses it.