What does it indicate when both dry bulb and wet-bulb temperatures are at 75 degrees Fahrenheit?

When both the dry bulb and wet-bulb temperatures are at 75 degrees Fahrenheit, it indicates that the air has reached a point of saturation with water vapor. This condition occurs when the wet-bulb temperature equals the dry bulb temperature. At this state, the air is unable to hold any more moisture, which results in 100% relative humidity.

Relative humidity is a measure of how much moisture is in the air compared to the maximum amount it can hold at a given temperature. When the wet-bulb and dry-bulb readings converge, it confirms that the moisture content in the air is at its maximum capacity, reflecting a saturated condition. Therefore, when both measurements are the same at 75 degrees, it signifies that the air is completely saturated with moisture, corresponding to 100% relative humidity, making the selection of this answer accurate.