From: "Met, (South Pole Station)" <Met@spole.gov>
To: South Pole All <summer99@Spole.gov>
Subject: SOUTH POLE MONTHLY CLIMATOLOGICAL SUMMARY FOR DEC 1999
Date: Sun, 2 Jan 2000 12:22:38 -0000 

SOUTH POLE STATION ANTARCTICA DECEMBER 1999 CLIMATE SUMMARY.

Temperature:
Avg temp................ -32.2(C)/-26.0(F)
Departure from normal... - 4.4(C)/-7.9(F)
Max temp................ -24.6(C)/-12.3(F) on day 22 
Min temp................ -42.0(C)/-43.6(F) on day 1 

Sky cover:
Avg cloud cover (8ths).... 4
Days clear................ 11
Days partly cloudy........ 12
Days cloudy............... 8

Wind:
Avg wind speed............. 8.4 mph or 7.3 kts.
Prevailing wind direction.. Grid north or 360 degrees.
Max wind................... 25 mph or 22 kts on days 4 and 5
Max wind direction......... Grid northwest.
Avg vectored wind.......... 031 degrees at 4.5 knots.

Station pressure:
Avg pressure........... 680.1 mb or 20.083 In. Hg.
Departure from normal.. -8.3 mb or -0.245 In. Hg.
Highest pressure....... 694.2 mb or 20.500 In. Hg. on day 17
Lowest pressure........ 670.0 mb or 19.785 In. Hg. on day 8

Physio-altitude in feet and meters:
Average physio-alt..... 10,625 ft/3238 m
Highest physio-alt..... 11,008 ft/3355 m on day 8
Lowest physio-alt...... 10,097 ft/3078 m on day 17

Sunshine:
Sunset on 20 March
Average hours/day......... 19.9
Percent of possible....... 83%

Snowfall..... Trace; avg net change at snow stakes -0.053 inches.

Visibility.... 0 days with visibility of 1/4 mile or less.

Balloon flight data:
Number of Soundings for the month... 62 
Avg height of Soundings.... 13.1 mb or 34324 meters above msl.
Highest Sounding........... 3.4 mb or 39777 meters above msl.
on the day 25/00z sounding.

Remarks:
0 Soundings were missed.
59 Soundings were terminated above the 50 mb level.
2 Soundings were terminated between 50 and 100 mb.
1 Sounding was terminated below the 100 mb level.

Records:

Day 1 - The minimum temperature of -42.0C/-43.6F is the coldest
temperature recorded in the month of December at the South Pole (records
go back to 1957). 

The average monthly temperature of -32.2C/-26.0F makes this the coldest
December on record. The previous record was -30.8C/-23.4F in 1985.

The average monthly pressure of 680.1 mb is lower than the previous
record low of 681.5 mb set in 1981. 

Following is a list of the 13 daily record low temperatures recorded
this month:

DAY TEMP C/F OLD RECORD C/F YEAR OF OLD RECORD
1 -42.0/-43.6 -38.9/-38.0 1965
2 -40.4/-40.7 -38.1/-36.6 1978
3 -39.3/-38.7 -38.9/-38.0 1978
9 -35.3/-31.5 -34.3/-29.7 1985
10 -35.5/-31.9 -33.9/-29.0 1973
12 -34.9/-30.8 -33.3/-27.9 1973
13 -34.8/-30.6 -32.8/-27.0 1977
14 -33.9/-29.0 -33.0/-27.4 1993
15 -32.5/-26.5 -32.2/-26.0 1959
26 -33.3/-27.9 -31.7/-25.1 1985
27 -33.6/-28.5 -30.9/-23.6 1980
28 -32.7/-26.9 -31.7/-25.1 1962
29 -32.4/-26.3 -31.7/-25.1 1998


Prepared by: John Gallagher