High pressure aloft started off the new year with high temperatures in the lower 70s.The first
storm of 2009 moved through the area on the 4th and 5th with valley rain and mountain snow.
Two day rainfall totals across the valley floor ranged from a quarter of an inch to a half an inch
while snowfall amounts above 6000 feet were in the 4 to 8 inch range. The low temperatures on 
the morning of the 7th were in the upper 20s to lower 30s.

High pressure aloft off the west coast would bring warmer daytime temperatures on the 8th and 
9th before a weak storm system moved through the Great Basin on the 10th and 11th resulting 
in cooler temperatures.

High pressure once again took control of the weather resulting in much above normal 
temperatures from the 15th to 21st. The high temperature of 80 degrees on the 19th was the 
first time Tucson hit 80 degrees or better in January since 2003. This warmth also translated 
to daily low temperatures with readings in the 50s from the 19th to the 24th. During this period, 
three daily high minimum temperature records were set (62 on 21st, 58 on 22nd and 56 on 
23rd). The 62 degrees on the 21st would set the all-time January high minimum temperature
record, shattering the old record of 57 degrees that was last set in 1965 on January 27th.

A Pacific storm system would bring valley rain and high elevation snow to the area late on the
21st through the 23rd. Three-day rainfall amounts for the area ranged from a tenth of an inch to
four-tenths of an inch. Highs on the 22nd and 23rd were in the upper 60s. On the morning of the 
24th the combination of warm moist air at the surface, light wind and a clear sky resulted in 
areas of dense fog with a few locations having visibilities down to one-quarter of a mile. A 
DENSE FOG ADVISORY was issued for the metro area.

The low temperature on the 25th of 46 degrees ended the consecutive day streak with daily lows
of 50 degrees or warmer at six straight. This eclipsed the old record of 4 straight which occurred 
in 1957 (8th through 11th).

A cooler but dry weather system would move through the area on the 26th and 27th. Low 
temperatures on the morning of the 28th were in the upper 20s to lower 30s, a huge change
from the previous record setting week.

The month ended with high pressure once again building in from the eastern Pacific. Overnight 
low temperatures moderated while daytime highs warmed into the lower to middle 70s at the 
close of the month.

January 2009 goes into the record books as the 4th warmest on record with an average monthly 
temperature of 55.5 degrees, which is 3.8 degrees above normal. Temperature extremes for the
month ranged from a high of 80 degrees on the 19th, 20th and 21st to a low of 31 degrees on 
the 28th.

Area rainfall totals for the month ranged from a half an inch to an inch and a third. Officially, the
International airport recorded just over six-tenths of an inch /0.63"/, which is over a third of an 
inch below normal.

January decade in review: the 2000s

The month of January during the decade of the 2000s will go into the record books as the 
warmest and 2nd driest decade on record  (dating back to the mid-1890s). The decadal average 
temperature of 53.2 degrees is two-tenths of a degree warmer than the 1990s. The average
decadal precipitation of 0.54" is a half an inch drier than the 1990s and is the driest decade since
the 1920s.

2003 (58.1°), 2009 (55.5°), and 2006 (54.5°) are ranked as the 2nd, 4th, and 6th warmest 
Januarys on record respectively. 2006 (Trace) ranks as the 6th driest (tied with 
1971/1958/1948) January on record.

The first two graphs below shows the daily departure from normal, or periods of warm/cold, for
each January day from 2000 through 2009. You can easily see why 2000, 2003, 2006 and 2009
were very warm while 2001 and 2007 were the only months that were well below normal. The 
third graph is the departure from normal for the monthly average temperatures. The fourth graph
is the departure from normal for the monthly rainfall. (all years compared against 1971-2000 
normals except 2000/2001 which were compared to 1961-1990 normals)

Temperature extremes for the decade ranged from 85 degrees on January 15, 2000 to 20 
degrees on January 15, 2007. Twenty-one records were set/tied this past decade. (listing below
is in chronological order). This is the most number of daily records set in a decade for January 
since 30 were set in the 1940s.

Glueck