We've been graphing the outside temperature at there spot where we plan to place the economizer. Although the temperature sensor is getting direct sunlight (you will see it gets over 110 degrees when the sun is shining on it) it's amazing that even during the middle of a hot summer, we would be able to turn on our air-side economizer at night. Notice from the graph (click on the image to enlarge it) that a little after midnight, the temperature drops near 65. This would be borderline but might allow us to cool the servers with outside air.