AWOS Sky Coverages

The Iowa DOT provides the IEM with an archive of 1 minute observations from their AWOS network. This archive contains numerically coded values for sky coverage. Unfortunately, there does not appear to be a definitive cross reference to match these values up to something humans can understand (ex. overcast). Here is our (Harry Hillaker and Daryl Herzmann) educated guess at a cross reference to what the sky coverage codes mean that are found in the archive.

Code Translated Code: Meaning
0NOREPORT No report, since lower cloud layers are obstructing.
1SCATTERED Scattered (10% to 50% coverage)
2BROKEN Broken (60% to 90% coverage)
4OVERCAST Overcast (More than 90% coverage)
8OBSCURATION Full obscuration (no ceiling or cloud amount available)
17OBSCURATION Partial obscuration, lowest cloud layer is scattered.
18OBSCURATION Partial obscuration, lowest cloud layer is broken.
20OBSCURATION Partial obscuration, lowest cloud layer is overcast.
32INDEFINITE Indefinite ceiling (no cloud cover amount available?)
64CLEAR No clouds below 12000 feet
128FEW Few (less than 10% coverage)
255MISSING Missing (sky condition not measured).
*UNKNOWNCODE All other values that may appear in the database.