This is a Weathercaster slide rule sold by George J Igel & Co. of Columbus, Ohio.  The date is unknown, I'd guess the 1960s.  To use it you position the red slide over the type of clouds observed.  Then you read the forecast on the rear of the device under the red slide, depending on the wind direction.  The algorithm was developed by Dr Irving P Krick. Various inserts are available on the rear of the device for the region of the US that you are in, this one is for the Great Lakes States.  It's made of plastic and is 10 inches long.  I believe this is a later, less expensive version of the Irving P Krick Weather Guide, shown elsewhere on this website.

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