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NOUS46 KLOX 171425
PNSLOX

Public Information Statement
National Weather Service Los Angeles/Oxnard CA
630 AM PST Fri Jan 17 2025

...A REMARKABLY DRY "RAINY" SEASON IS UNDERWAY IN SOUTHWESTERN
CALIFORNIA...

Much of southwestern California is experiencing a record or near-
record beginning to its rainy season. It is rather well known that
very little rain falls in southern California from late April
through early November.

In Downtown Los Angeles, average rainfall from May through October
(based on the 30-year average) totals only 1.14 inches, with less
than a quarter of an inch of rain (0.24 inch) on average from June
through September. There have been many years with no measurable
rain whatsoever during that 4  month period.

Most of the yearly rainfall in southwestern California, especially
west of the mountains, falls from December through March. On
average, Downtown Los Angeles receives 11.64 inches during this 4
month period, about 82% of its yearly average of 14.25 inches.

Despite our typically dry conditions during the warm season,
rainfall since last May has been historically scarce. Here are some
rather grim statistics highlighting the lack of rainfall in Downtown
Los Angeles, which has been representative of most of the stations
in Los Angeles County, Ventura County, and the south coast of Santa
Barbara County.

In Downtown Los Angeles, the last day on which one tenth of an inch
of rain (0.10 inch) was recorded was back on May 5th, 2024, a
whopping 255 days ago. That just recently exceeded the previous
record of 253 consecutive days without a tenth of an inch of rain,
from February 25th through November 3rd, 2008.

Downtown Los Angeles went a full 180 days without any measurable
rain after May 5th, as measurable rain did not occur again until
November 1st, 2024. That was not a record, but it was the 7th
longest stretch without measurable rain. The longest stretch of
consecutive days without measurable rain was 219 days, from February
18th through September 24th, 1997. The second longest stretch was
197 days, from April 13th through October 26th, 1927.

For the official water year (October 1st through September 30th of
the following year), rainfall through January 15th totaled a scant
0.16 inch, or just 3% of the average rainfall of 5.56 inches from
October 1st through January 15th.

That places it in a tie with the 1962-1963 water year as the second
driest to that date. The driest water year to date was the 1903-1904
water year, during which only a trace of rain was received between
October 1st 1903 and January 15th, 1904.

For those who use the July 1st through June 30th time period to
define the rainy season, the 0.16 inch of rain between July 1st,
2024 and January 15th, 2025 is tied with July 1st 1962 through
January 15th, 1963 as the driest such time period. The 1903-1904
season was 3rd driest, with 0.43 inch of rain during those dates,
all in the 4th week of September 1903.

The following table of selected locations in southwestern California
shows total rainfall for the water year from October 1st through
January 15th, average rainfall during this period, the percentage of
normal rainfall for the period, the ranking of this start to the
water year through January 15th.

The season with the driest such start will be denoted in
parenthesis. If this is the driest, the previous driest will be
denoted in parentheses.

                   TOTAL     AVG     % NORM     RANK OF
                   RAIN      RAIN    RAIN       DRYNESS     (driest
                  10/01/24   10/01   10/01      10/01        water
                    THRU     THRU    THRU        THRU        season
LOCATION          01/15/25   01/15   01/15      01/15        to date)

----------------------------------------------------------------------

L.A. Downtown       0.16     5.56     3%    (tie) 2nd driest (1903-04)
L.A. Intl AP        0.03     5.04     1%    Driest  (previous 1962-63)
Long Beach AP       0.08     4.90     2%          2nd driest (1962-63)
UCLA                0.10     6.36     2%    Driest  (previous 1962-63)
Burbank AP          0.09     4.80     2%          2nd driest (1962-63)
Van Nuys AP#        0.05     4.49     1%    Driest  (previous 1999-00)
Woodland Hills      0.16     5.96     3%    Driest  (previous 1962-63)
Lancaster AP          T      2.57     0%    Driest  (tie with 1962-63)
Palmdale AP         0.02     2.36     1%          2nd driest (1999-00)
Sandberg            0.28     4.71     6%          2nd driest (1962-63)
Camarillo AP        0.31     4.54     7%    Driest  (previous 1975-76)
Oxnard NWS          0.49     5.76     9%          3rd driest (1962-63)
Santa Barbara AP    0.64     6.94     9%          3rd driest (1962-63)
Santa Maria AP      1.54     5.09    30%          7th driest (2013-14)
San Luis Obispo AP+ 2.92     7.63    39%          7th driest (2013-14)
Paso Robles AP      2.01     4.79    42%         13th driest (2013-14)

T - trace of rain, not measurable

# Period of observations less than 30 years (29 years)
+ Period of observations less than 30 years (27 years)

$$

Bruno/Sirard