Narrative Summary - May 1999

May 1999 was cooler than normal, averaging 57.9ºF, 3.4º below normal (61.3ºF). The
first three weeks of the month averaged 7.2º below normal, with the first above normal
day for the month not occurring until May 22. The warmest May occurred in 1947 and
averaged 68.7ºF, while the coolest was 56.0ºF in 1984. The following daily temperature
records were established in May:

                          New          Old
Date   Category          Record       Record     Year
  7    Low Maximum	   59		61	 1990
  8    Low Maximum	   56		56	 1962  Tie
  9    Low Minimum    	   34		34	 1996  Tie
 24    High Maximum	   97		96	 1962

Precipitation for May 1999 totaled 0.34 in., 67% of normal (0.51 in.). The wettest May,
in 1972, received 2.03 in., while the driest, in 1992 and earlier years, received only a
trace. Total precipitation since January 1 was 1.99 in., 71% of normal (2.80 in.).

The average wind speed for May 1999 was 10.4 miles per hour (mph), 1.3 mph above
normal (9.1 mph). The windiest May on record averaged 10.7 mph (1983), while the May
with the lightest winds (1957) averaged 5.8 mph. The peak gust for the month was 45
mph on May 25. The record wind gust for May was 71 mph in 1948.

Spring 1999 (March, April and May) was cooler than normal, averaging 51.7ºF, 1.5º below
normal (53.2ºF). The warmest spring, in 1992, averaged 58.2ºF, while the coolest (1955)
averaged 48.0ºF. Spring 1999 was the 6th driest on record with precipitation totaling 0.40
in., 29% of normal (1.40 in.). The wettest spring, in 1995, received 3.28 in., while the
driest (1968) received only 0.09 in.

The monthly climatological data summaries, as well as other information, are available
on the Internet. Address: http://etd.pnl.gov:2080/HMS/. Hanford Site personnel can
access the HMS Intranet site at: http://hms.rl.gov/

For additional information contact:
Ken Burk373-3215
Dana Hoitink372-6414

Note: The information in this summary pertains specifically to
the Hanford Meteorology Station (HMS), which is located
approximately 25 miles northwest of Richland, Washington. No
attempt should be made to infer meteorological conditions at other
locations from these data.