1. A method for determining atmospheric conditions from an image, the method comprising: identifying a set of pixels surrounding a horizon depicted in an image frame, the set of pixels including a plurality of rows in a first subset of pixels above the horizon in the image frame and a plurality of rows in a second subset of pixels below the horizon in the image frame; determining an intensity value for each pixel in the set of pixels; calculating an average of the intensity values for each of a specified number of rows of the pixels in the first subset and an average of the intensity values of the pixels for each of the specified number of rows of the pixels in the second subset; determining a first slope of the averages calculated for the first subset; determining a second slope of the averages calculated for the second subset; and calculating a difference between the first slope and the second slope to determine atmospheric conditions.