Description:
The maps above show the monthly station temperature anomalies (top) and percentiles (bottom) with respect to the 1971-2000 climatology. The percentiles shown indicate a ranking of  temperature anomalies (for the month shown on plot) with the 0th percentile being the coldest on record and the 100th percentile (shown as 1 on the plot) being the warmest.  Stations shaded in orange or red indicate monthly temperature above the 80th percentile, and stations shaded in blue tones indicate temperature below the 20th percentile.

The period used for computing the percentiles is 1971-2000.  "CAMS" is an acronym for the "Climate Anomaly Monitoring System" in use at the Climate Prediction Center (CPC) at the US National Centers for Environmental Prediction (NCEP).