WHEN RAINS MAY BE EXPECTED 29 



in this place, because it is possible now to secure the data from 

 different sources. Local observers almost everywhere can furnish 

 the facts. It is, however, pertinent to present a general compilation 

 which fixes approximately the date at which effective rains may be 

 expected in each main division of the state and thus impart a some- 

 what definite notion of when the natural season of growth will begin. 

 All should be in readiness beforehand to seize upon this opportunity 

 for soil working, if one is to proceed without irrigation, and for the 

 planting of seeds of hardy vegetables which will withstand the local 

 winter temperature and give the earliest readiness for use under the 

 circumstances. 



When the First Rains May Be Expected. The rainfall at San 

 Francisco is very close to the mean between the heavy and light 

 rainfall of the state; hence it represents very largely the whole 

 state. Considering the record of the United States Weather Ob- 

 server, it is found by Mr. Page that during a twenty-five year period 

 ending in 1895, the average date of first 0.05 of an inch of rainfall 

 occurs by September 17. Considering June 30 as the official end of 

 one season and July 1 the commencement of the next season, the 

 earliest date of 0.05 of an inch of rain is July 8, 1885, and the latest 

 October 27, 1875 that is, from July 1 to October 27, 1875, only 

 0.05 of an inch of rain fell. As 0.05 of an inch of rain is such a 

 small amount, it has been deemed best to consider that when one- 

 quarter (0.25) of an inch of rain has fallen that date be considered 

 the commencement of the rainy season. Using this, then, as a basis, 

 we find that the rainy season begins on October 8. The earliest 

 date of a quarter of an inch is September 8, 1884, and the latest 

 not until November 23, 1880. 



As one-quarter of an inch of rainfall at San Francisco is hardly 

 sufficient to allow of rainfall over the southern portion of the state, 

 a basis of one inch at San Francisco was considered for the south- 

 ern portion as the commencement of the rains there, and this is 

 found to be November 1. The earliest date of one inch of rain is 

 September 15, 1888, and the latest December 3, 1890. 



One inch of rainfall at San Francisco is not sufficient for the 

 interior of the state to allow of good plowing and seeding; hence 

 a total of two inches at San Francisco was considered, and it is 

 found that two inches of rain falls at San Francisco up to Novem- 

 ber 1 ; hence that date can be said to be the date of commencement 

 of good plowing. 



Five inches is considered to indicate that the rainy season has 

 entered upon full effect, and it is found that five inches does not fall 

 before December 15, and that the earliest date that five inches has 

 fallen is October 21, 1889, and the latest February 5, 1891. In this 

 latter season February was very wet, and the total for the season 

 was seventeen fifty-eight hundredths inches. 



To summarize, we have first rains September 17; rainy season 

 begins October 8, and in southern portion of state November 1 ; 



