Note: The data presented in this report are preliminary. Ranks and anomalies may change as more complete data are received and processed. Effective September 2012, the GHCN-M version 3.2.0 dataset of monthly mean temperature replaced the GHCN-M version 3.1.0 monthly mean temperature dataset. Beginning with the August 2012 Global monthly State of the Climate Report, released on September 17, 2012, GHCN-M version 3.2.0 is used for NCDC climate monitoring activities, including calculation of global land surface temperature anomalies and trends. For more information about this newest version, please see the GHCN-M version 3.2.0 Technical Report.
*The GHCN-M version 3.1.0 Technical Report was revised on September 5, 2012 to accurately reflect the changes incorporated in that version. Previously that report incorrectly included discussion of changes to the Pairwise Homogeneity Algorithm (PHA). Changes to the PHA are included in version 3.2.0 and described in the version 3.2.0 Technical Report. Please see the Frequently Asked Questions to learn more about this update.
The global mean temperature for March through May,
1999, was well above the long-term average, based on preliminary
data. Yet, this 3-month global mean temperature was considerably
cooler than the record warmth experienced in March through May of
1998, largely due to cooler sea surface temperatures this year. See
the Global Analysis for more details.
Based on the long-term mean (1880-1998), the March through May,
1999, land and ocean temperature was 0.8 C above average; 0.3 C
less than the record global temperature recorded in 1998.
|Based on preliminary
data, precipitation on the global land surface was also above
average during the period March through May. Based on the 1900 to
1998 long-term mean, global precipitation was over 7 mm above
average. See the Global Analysis and
Global Regional Analysis pages
for more details on the global climate.
|For the three-month
period March through May, 1999, the mean temperature for the
contiguous U.S. was nearly 0.6 F above the long-term average, based
upon preliminary data. The bars in this graph are departures from
the 1895-1998 mean. The curved line is a nine-point binomial filter
which shows the decadal-scale variations.
precipitation for the contiguous U.S. for the period March through
May, 1999, was more than 0.5 inches below the long-term average,
based on preliminary data. The bars in this graph are departures
from the 1895-1998 mean. The curved line is a nine-point binomial
filter which shows the decadal-scale variations. See the U.S. National Analysis and U.S. Regional / Statewide Analyses pages for
more details on the U.S. climate.
Extreme climatic events during the period March through
May included: floods and landslides in Europe in March; floods in
the Phillipines, Columbia and Venezuela in April; snowstorms in the
U.S.; persistent, severe, or developing drought in many areas of