The Los Angeles thermogram and hygrogram of the four- 

 day period presents an excellent example of the relationship 

 between temperature and moisture in Southern California 

 during days when the thermometer rises above 90 degrees. 

 The trace sheets of the thermograph and hygrograph show 

 that the day preceding and following the hot day were normal 

 September days with moderately high temperatures, 99 and 

 90 degrees, and nearly normal humidities, 66 per cent, and 65 

 per cent. At 1 :30 P. M. on September 17, the time of the 

 highest temperature of 108 degrees, the relative humidity was 

 4 per cent, as determined by whirled psychrometer observa- 

 tions. 



Growers of vegetables and tender plants suffered loss 

 by the extreme drvness, and some of the walnut groves sus- 

 tained damage. The physical efifect of the hot and drv air 

 was not detrimental to the health or business activities of the 

 community. There was an absence of prostration cases from 

 the hospital records and business progressed without inter- 

 ruption. Owing to the extreme dryness of the air animals 

 did not suffer from the heat except rabbits, many of them 

 dying from the unusual conditions. Incidentally there was 

 considerable financial loss occasioned by forest and city fires. 

 On the day of the greatest heat the city fire department re- 

 sponded to 21 fires, which necessitated the use of about 75 mil- 

 lion gallons of water, equaling the amount used for domestic 

 purposes by the city on a normal day. 



Is the Climate Changing? 



A perusal of the foregoing account of the weather ex- 

 tremes in Southern California during the present vear may 

 well stimulate the popular inquiry, 'Ts the climate changing?" 

 While it is true that here in Los Angeles we have equaled 

 the lowest temperature ever known as well as the highest 

 (within one decree) ever experienced, also the hottest night 

 on record in this localitv, and registered the heaviest twenty- 

 four-hour rainfall, all since the first of the year, this does 

 not indicate a change in the general equability of local 

 meteorological conditions. 



There are fluctuations from a normal, both in temperature 

 and rainfall, but these departures are neither periodic nor 

 cumulative. It is readily seen from the accompanying chart 

 showing profiles of maximum, average and minimum tempera- 

 tures at Los Angeles for over a generation that there is no 

 general diminution or increase in temperature. In fact, as 

 regards mean temperature it will be noticed that the tem- 

 perature varies only a few degrees from vear to vear. The 

 warmest year in Los Angeles was that of 1877, with an aver- 



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