How long does water take to evaporate in a room?

How Long Does Water Take to Evaporate Indoors?

If you have ever left a glass of water sitting on your bedside table, you might have noticed the water level slowly dropping over time. Wondering how fast that actually happens comes down to a few basic environmental factors, most notably temperature and humidity.

At a comfortable room temperature typically ranging between 68 and 72 degrees Fahrenheit, moisture leaves an exposed water surface at a steady pace. Under these standard indoor conditions, a small amount—about 0.1 ounces—evaporates every 1.2 hours.

To put that into perspective, think about a standard kitchen measuring cup filled with 8 ounces of water. At that exact evaporation rate, it takes roughly 9 days and 6 hours for the entire cup to completely disappear into the air as vapor.

Keep in mind that this timeline can change quite a bit depending on your surroundings. If your room has high humidity, a drafty ceiling fan, or direct sunlight shining through a window, the evaporation process will speed up or slow down accordingly.