2m Temperature refers to air temperature at 2 meters above the surface. 2m Temperature Anomaly refers to
the departure of the current day's forecasted temperature from a long-term mean for the same day of the year. The
anomalies here are based on a 1979-2000 reference climatology derived from the
NCEP Climate Forecast System Reanalysis (CFSR). This 22-year baseline is used instead of the more common 1981-2010
climate normal because 1979-2000
represents conditions prior to rapid Arctic warming and sea-ice loss. A comparison of different climate baselines
against the historical temperature record is shown here.
The daily temperature anomaly values shown on these maps reflect current weather patterns, and therefore global
and regional means can vary significantly from day-to-day and week-to-week. Climate trends should only be inferred from
long-term datasets, such as those available on the
Monthly Reanalysis Timeseries page.
Please also refer to NOAA's Climate at a Glance
for verified data on monthly, seasonal, and annual temperature change since 1880.
Temperature anomalies calculated between GFS (forecast) and CFSR (reanalysis) will differ somewhat from those calculated
entirely within the Climate Forecast System framework (see
this NCEP/NWS discussion on model bias). For the most reliable daily temperature anomaly estimates, refer to
the Daily Reanalysis Maps page.
The image archive is updated once or twice per month.
Sea Surface Temperature (SST) and SST anomaly maps are generated from
NOAA Optimum Interpolation SST version 2 (OISST V2).
OISST is a 0.25° gridded dataset derived by blending satellite, ship, and buoy measurements. The SST anomalies
is based on a 1971-2000 climatology calculated by NOAA.