The height to which grass will grow as a result of an inch of rain can vary depending on various factors, such as the type of grass, environmental conditions, and existing soil conditions. However, on average, grass can grow about 1/4 to 1/2 inch in response to an inch of rain.
It's important to note that the growth of grass is not solely determined by the amount of rain it receives. Other factors like temperature, sunlight, soil nutrients, and the health of the grass itself also play significant roles in determining its growth rate.