ISMCS Station Climatic Narrative for San Diego

          The city of San Diego is located on San Diego  Bay      
          in the southwest corner  of  southern  California.      
          The prevailing winds and weather are  tempered  by      
          the Pacific Ocean, with the  result  that  summers      
          are cool and winters warm in comparison with other      
          places   along   the   same   general    latitude.      
          Temperatures of  freezing  or  below  have  rarely      
          occurred  at the station  since  the  record began      
          in 1871, but hot weather, 90 degrees  or above, is      
          more frequent.                                          
                                                                  
          Dry easterly winds sometimes blow in the  vicinity      
          for several days at a time, bringing  temperatures      
          in the 90s  and at times even in the 100s  in  the      
          eastern sections of the city and outlying suburbs.      
          At the National Weather  Service  station  itself,      
          however, there have been relatively  few  days  on      
          which 100 degrees or higher was reached.                
                                                                  
          As these hot winds are predominant  in  the  fall,      
          highest  temperatures  occur  in  the  months   of      
          September and  October.  Records show that over 60      
          percent of the days with 90 degrees or higher have      
          occurred in these two months.   High  temperatures      
          are almost  invariably  accompanied  by  very  low      
          relative humidities, which  often  drop  below  20      
          percent and occasionally below 10 percent.              
                                                                  
          A marked  feature  of  the  climate  is  the  wide      
          variation in temperature within  short  distances.      
          In nearby valleys  daytimes  are  much  warmer  in      
          summer and nights noticeably cooler in winter, and      
          freezing occurs much more frequently than  in  the      
          city.  Although records show unusually small daily      
          temperature ranges,  only about 15 degrees between      
          the highest  and  lowest  readings,  a  few  miles      
          inland these  ranges  increase  to  30  degrees or      
          more.                                                   
                                                                  
          Strong winds and gales associated with Pacific, or      
          tropical  storms,  are  infrequent  due   to   the      
          latitude.                                               
                                                                  
          The seasonal rainfall is about 10  inches  in  the      
          city, but increases with  elevation  and  distance      
          from the coast. In  the  mountains  to  the  north      
          and east the average is between 20 and 40  inches,      
          depending on slope and elevation.    Most  of  the      
          precipitation  falls  in  winter,  except  in  the      
          mountains   where   there   is    an    occasional      
          thunderstorm.     Eighty-five   percent   of   the      
          rainfall occurs from November through  March,  but      
          wide variations take place in monthly and seasonal      
          totals.  Infrequent  measurable  amounts  of  hail      
          occur  in  San  Diego,  but  snow  is  practically      
          unknown  at the Weather Service  Office  location.      
          In each  occurrence of  snowfall  only a trace was      
          recorded officially, but in some locations amounts      
          up to or  slightly exceeding a half-inch fell, and      
          remained on the ground for an hour or more.             
                                                                  
          As on the rest of the Pacific  Coast,  a  dominant      
          characteristic  of  spring  and  summer   is   the      
          nighttime  and  early  morning  cloudiness.    Low      
          clouds form regularly and frequently extend inland      
          over the coastal valleys and foothills,  but  they      
          usually  dissipate  during  the  morning  and  the      
          afternoons are generally clear.                         
                                                                  
          Considerable fog occurs along the coast,  but  the      
          amount decreases with distance inland.   The  fall      
          and  winter  months  are  usually  the   foggiest.      
          Thunderstorms are rare, averaging  about  three  a      
          year in the city.   Visibilities  are  good  as  a      
          rule.  The sunshine  is  plentiful  for  a  marine      
          location,  with  a  marked  increase  toward   the      
          interior.     
		                                            
--------------------------------------------------------------

Percent Frequency Daily PRECIPITATION AMOUNTS for Lindbergh Field


POR: : 1948-1990

                                                                                               PERCENT  TOTAL         TOTAL
                                                                                               OF DAYS   NO.          PRECIP
                                                                                                WITH     OF          (INCHES)
                                              INCHES                                           AMOUNTS   OBS   MEAN    HI     LOW  
      NONE  TRACE    .01  <=.05  <=.10  <=.25  <=.50  <=1.0  <=2.5  <=5.0 <=10.0 <=20.0  >20.0  >=.01  

JAN   71.3    6.5    2.0    4.7    3.4    4.1    4.1    2.6    1.2     .1      0      0      0  22.1    1333   1.95   5.95      T
FEB   72.7    8.2    2.2    3.2    3.4    4.6    2.1    2.9     .8      0      0      0      0  19.1    1203   1.43   5.40      0
MAR   70.0    8.7    2.3    4.1    3.5    4.8    3.2    2.6     .9      0      0      0      0  21.3    1333   1.69   6.57      T
APR   74.7   10.4    2.8    3.6    2.6    2.9    1.7     .9     .4      0      0      0      0  14.9    1290    .79   3.71      T
MAY   79.1   13.8    2.3    2.4    1.1     .6     .6     .1     .1      0      0      0      0   7.1    1333    .20   1.79      0
JUN   83.3   13.5    1.2    1.1     .3     .3     .3      0      0      0      0      0      0   3.3    1290    .06    .87      0
JUL   92.3    6.6     .5     .4     .2     .1      0      0      0      0      0      0      0   1.1    1333    .01    .19      0
AUG   93.0    5.3     .4     .5     .2     .3     .1     .2     .1      0      0      0      0   1.7    1333    .10   2.13      0
SEP   88.1    7.8     .5    1.5     .6     .7     .5     .3      0      0      0      0      0   4.1    1290    .19   1.90      0
OCT   85.7    6.9    1.6    2.1     .7    1.7     .5     .9      0      0      0      0      0   7.4    1333    .38   1.76      0
NOV   78.8    5.6    2.0    3.1    1.9    3.1    3.2    1.6     .9      0      0      0      0  15.7    1290   1.24   5.82      0
DEC   76.9    5.9    1.5    3.6    2.4    3.8    3.3    1.7     .8      0      0      0      0  17.1    1330   1.41   6.60    .02
ANN   80.5    8.3    1.6    2.5    1.7    2.2    1.6    1.1     .4      *      0      0      0  11.2   15691   9.46  19.41   3.41


* = PERCENT < .05  
T = ZERO PRECIP, SNOWFALL OR SNOW DEPTH MEASURED BUT A TRACE WAS NOTED
+ = ANNUAL HI AND LOW VALUES ARE DERIVED FROM ANNUAL TOTALS
# = EXCESSIVE MISSING DATA - VALUE NOT COMPUTED

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

Cumulative Percent Frequency Daily MINIMUM TEMPERATURES at Lindbergh Field

POR: : 1948-1990

Temp(F)  JAN  FEB  MAR  APR  MAY  JUN  JUL  AUG  SEP  OCT  NOV  DEC  ANN

   >=75    0    0    0    0    0    0   .3  1.1  1.6    0    0    0   .2
   >=70    0    0    0    0    0   .9  9.2 15.4 11.6   .7    0    0  3.2
   >=65    0    0    0   .2  2.0 12.1 55.2 74.5 51.9 16.1   .4    0 17.9
   >=60  1.7  1.4  2.3 10.8 36.5 76.1 97.6 99.6 92.0 55.9  9.3  1.4 40.6
   >=55 13.4 17.6 30.5 61.0 89.4 99.1  100  100 99.8 90.6 42.9 13.1 63.4
   >=50 41.3 51.5 72.3 93.4 99.5  100  100  100  100 99.2 79.2 39.2 81.4
   >=45 74.7 87.1 96.0 99.7  100  100  100  100  100 99.9 97.3 81.3 94.7
   >=40 94.8 98.3 99.9  100  100  100  100  100  100  100 99.8 96.5 99.1
   >=35 99.5  100  100  100  100  100  100  100  100  100  100 99.8 99.9
   >=30 99.9  100  100  100  100  100  100  100  100  100  100  100  100
   >=25  100  100  100  100  100  100  100  100  100  100  100  100  100
   MEAN 48.2 49.8 52.0 55.1 58.3 61.4 65.1 66.5 64.8 60.1 53.4 48.6 57.0
   STDV  5.4  4.7  4.1  3.5  3.0  2.8  3.1  3.0  3.9  4.3  4.6  4.8  7.5
   #OBS 1333 1203 1333 1290 1333 1290 1333 1332 1290 1333 1290 133015690


* = PERCENT < .05  
# = EXCESSIVE MISSING DATA - VALUE NOT COMPUTED

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

Cumulative Percent Frequency Daily MAXIMUM TEMPERATURES at Lindbergh Field

POR: : 1948-1990

Temp(F)  JAN  FEB  MAR  APR  MAY  JUN  JUL  AUG  SEP  OCT  NOV  DEC  ANN

  >=110    0    0    0    0    0    0    0    0   .1    0    0    0    *
  >=105    0    0    0    0    0    0    0    0   .2   .1    0    0    *
  >=100    0    0    0    0    0   .2    0    0   .8   .4    0    0   .1
   >=95    0    0    0   .2   .1   .5   .2   .1  1.6  1.1   .2    0   .3
   >=90    0    0   .2   .7   .6  1.4   .7   .5  4.2  2.9  1.0    0  1.0
   >=85   .3   .7   .5  1.9  1.5  2.0  3.9  4.6 10.7  7.6  3.6   .4  3.1
   >=80  4.1  4.0  2.8  5.2  3.5  5.5 17.3 24.7 25.7 14.9  9.8  3.2 10.1
   >=75  9.8 10.5  8.2 10.9  9.1 17.9 63.2 79.1 61.9 35.7 22.1 10.5 28.4
   >=70 22.1 24.5 20.4 29.5 37.9 70.2 98.4 99.8 97.5 84.2 45.5 26.7 54.9
   >=65 47.9 55.4 58.7 77.8 92.9 98.8  100  100  100 99.4 86.7 60.1 81.6
   >=60 85.4 91.3 96.3 99.4 99.9  100  100  100  100  100 99.4 90.3 96.8
   >=55 98.5 99.6  100  100  100  100  100  100  100  100  100 99.5 99.8
   >=50 99.8  100  100  100  100  100  100  100  100  100  100  100  100
   >=45  100  100  100  100  100  100  100  100  100  100  100  100  100
   MEAN 65.3 66.2 66.3 68.2 69.2 71.7 76.1 77.5 77.1 74.2 70.5 66.5 70.8
   STDV  6.2  5.9  5.2  5.4  4.3  4.6  3.9  3.7  5.7  5.9  6.2  5.9  6.8
   #OBS 1333 1203 1333 1290 1333 1290 1333 1333 1290 1333 1290 133015691


* = PERCENT < .05  
# = EXCESSIVE MISSING DATA - VALUE NOT COMPUTED

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

San Diego Lindbergh Field Summary of Various Climate Factors 

POR: (HOURLY): 1948-1990 

    TEMPERATURE (DEG F)|    PRECIPITATION (INCHES) (^)  |REL HUM|VAP|DEW| PR |WIND (KTS) |   |      MEAN NO. OF DAYS WITH (&)
       MEANS   |EXTREME|       PRECIP.     |SNOWFALL (@)|PERCENT|PR |PT.| ALT|           |SKY|PRECIP.|SNOW-  |   |   |  TEMP (DEG F)
       |   |   |   |   |     |    |    |24H|    |   |24H| (LST) |IN.|(F)| FT.|PREVAIL|MAX|CVR|INCHES |FALL(")|TH |FOG|MAX|MAX|MIN|MIN
    MAX|MIN|AVG|MAX|MIN| MEAN| MAX| MIN|MAX|MEAN|MAX|MAX| AM| PM|HG.|   |  $ |DIR|SPD|GST| + | >=| >=| >=| >=|STM| * | >=| >=| <=| <=
                                                        | 07| 16|                            |.01|.50|.10|1.5|       | 90| 70| 32| 10

JAN  65  48  57  88  29   1.9  5.9    T 2.6    T   T   T  70  57 .28  43   20  NW   7  56 CLR   7   1   0   0   #  10   0   7   #   0
FEB  66  50  58  88  36   1.4  5.4    0 1.7    0   0   0  72  58 .30  45   20 WNW   8  45 CLR   5   1   0   0   #   9   0   7   0   0
MAR  66  52  59  93  39   1.7  6.6    T 2.1    0   0   0  73  59 .32  47   25 WNW   9  46 OVR   7   1   0   0   #   7   #   6   0   0
APR  68  55  62  98  44    .8  3.7    T 1.4    0   0   0  72  59 .36  50   20 WNW   9  37 OVR   4   #   0   0   #   6   #   9   0   0
MAY  69  58  64  96  48    .2  1.8    0 1.5    0   0   0  73  63 .40  53   20 WNW   8  35 OVR   2   #   0   0   #   6   #  12   0   0
JUN  72  61  67 101  51    .1   .9    0  .5    0   0   0  77  66 .46  57   20 WNW   8  32 OVR   1   0   0   0   #   7   #  21   0   0
JUL  76  65  71  95  55     T   .2    0  .1    0   0   0  79  65 .54  61   20 WNW   8  26 OVR   #   0   0   0   #   6   #  31   0   0
AUG  77  66  72  98  58    .1  2.1    0 1.4    0   0   0  79  66 .56  62   20 WNW   8  29 OVR   1   #   0   0   #   6   #  31   0   0
SEP  77  65  71 111  51    .2  1.9    0  .9    0   0   0  78  65 .53  61   25 WNW   8  38 CLR   1   #   0   0   #   8   1  29   0   0
OCT  74  60  67 107  43    .4  1.8    0 1.0    0   0   0  74  63 .44  55   20 WNW   8  35 CLR   2   #   0   0   #  11   1  26   0   0
NOV  71  53  62  97  38   1.2  5.8    0 2.0    0   0   0  69  60 .33  48   20 WNW   8  42 CLR   5   1   0   0   #  10   #  14   0   0
DEC  66  49  58  88  34   1.4  6.6    T 2.1    T   T   T  68  58 .28  43   25  NW   7  38 CLR   5   1   0   0   #  11   0   8   0   0
ANN  71  57  64 111  29   9.5 19.4  3.4 2.6    T   T   T  74  62 .39  52   30 WNW   8  56 OVR  40   6   0   0   5  97   4 201   #   0
POR  43  43  43  43  43    43   43   43  43   43  43  43  43  43  43  43   43  43  43  21  43  43  43  43  43  43  43  43  43  43  43


T = TRACE AMOUNTS ( < .05  < .5 INCHES  
# = MEAN NO. DAYS < .5 DAYS 
$ = PRESSURE ALTITUDE IN TENS OF FEET (I.E.  50 = 500 FEET) 
@ = NAVY STATIONS REPORT HAIL AS SNOWFALL; ALSO NWS FROM JULY,1948 - DEC.,1955
+ = THE PREDOMINANT SKY CONDITION
* = VISIBILITY IS NOT CONSIDERED
& = ANN TOTALS MAY NOT EQUAL SUM OF MONTHLY VALUES DUE TO ROUNDING 
^ = 24 HR MAX PRECIP AND SNOWFALL ARE DAILY TOTALS (MID-NIGHT TO MID-NIGHT)  
I = EXCESSIVE MISSING DATA - VALUE NOT COMPUTED
" = INCHES

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

Number of Days per Month of PRECIPITATION & OBSTRUCTION TO VISION
for San Diego Lindbergh Field  

POR: (HOURLY): 1948-1990 

             MEAN NO. OF DAYS WITH (&)          |   
          PRECIPITATION     |  OBSTR TO VISION  |   
        |FRZ |    |HAIL|    |SMOK|BLOW|DUST| OBS|   
    R/DZ|R/DZ|SNOW|/SLT|PRCP|HAZE|SNOW|SAND| VIS|   

JAN    9    0    #    #    9   11    0    0   14
FEB    8    0    0    #    8   10    0    0   14
MAR    9    0    0    #    9    9    0    0   12
APR    8    0    0    #    8    8    0    0   10
MAY    6    0    0    0    6   10    0    0   11
JUN    5    0    0    0    5   13    0    0   15
JUL    2    0    0    0    2   17    0    0   17
AUG    2    0    0    0    2   16    0    0   17
SEP    4    0    0    #    4   16    0    0   17
OCT    4    0    0    #    4   16    0    0   18
NOV    6    0    0    #    6   13    0    0   16
DEC    7    0    #    #    7   13    0    0   16
ANN   70    0    #    #   70  152    0    0  177
POR   42   42   42   42   42   42   42   42   42


& = ANN TOTALS MAY NOT EQUAL SUM OF MONTHLY VALUES DUE TO ROUNDING 
I = EXCESSIVE MISSING DATA - VALUE NOT COMPUTED
# = MEAN NO. DAYS < .5 DAYS