Source: Player's Handbook
1st-level conjuration
Casting Time:
1 action
Range:
120 feet
Components:
V, S
Duration:
Concentration, up to 1 hour
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.
At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, the radius of the fog increases by 20 feet for each slot level above 1st.