Autumn months are the most pleasant as the 

 "Pacific highs" infiltrate this area with slight 

 breezes, blue smogless sky, and warm daytime 

 temperatures. Below -freezing temperatures 

 (as low as 10* F.) are common in the early 

 morning hours . 



Winter is characterized by moderate snow- 

 fall with average depths of 2 to 4 feet. Subfreez- 

 ing temperatures prevail, and strong, gusty 

 winds are common . These winds usually pre - 

 cede and follow low-pressure systems swinging 

 southeasterly across northern and central Cal- 

 ifornia. The lakes in this general area and 

 elevation, 7,000 feet, usually freeze over by 

 mid-December, and the streams are almost 

 hidden by drifting snow. Januar> is normally 

 the coldest month of the year. Figure 3 shows 

 a severe winter scene at Convict Creek Station. 



Mean water temperatures for the 13 -year 

 period are shown in table 1 by months and by 

 years, and for the entire period. Mean air 

 temperatures are similarly tabulated in table 2, 

 together with annual number of hours below 32° F. 

 Mean flows are similarly shown in table 3 along 

 with annual run -off in acre -feet. 



Mean temperatures and flow data are pre- 

 sented in tables 4,5, and 6 by months, monthly 

 minima and maxima, semiannual, annual, and 

 totals for the period. 



Daily and mean monthly maximum and 

 minimum water and air temperatures are pre- 

 sented for the 13-year period in tables 7 to 32, 

 along with monthly means . Mean daily and 

 monthly rate of flow and monthly volume of flow 

 are shown in tables 33 to 45 . 



At this elevation, the spring season is char- 

 acterized by unsettled weather with snowstorms, 

 rain, sleet, subfreezing temperatures, and 

 gusty winds . Spring thaw begins in late March, 

 and lakes and streams are usually open by late 

 April. Daytime temperatures gradually climb 

 to a comfortable level by June, but freezing 

 temperatures may be expected during the early 

 morning hours . 



EQUIPMENT AND METHODS 



Air and water temperatures were taken with 

 a recording thermograph with a range of to 

 100* F., graduated in 1* intervals. Recorded 

 temperatures were read to the nearest of 0.5'F. 

 The thermograph was calibrated every 4 months 

 with a resistance thermometer . Supplementary 

 temperatures were taken with a maximum -mini - 

 mum thermometer when the thermograph was 

 inoperative and during low air temperature 

 periods . 



The flow-gaging station on Convict Creek, 

 maintained by the Department of Water and 

 Power of the City of Los Angeles, is located 

 l~]/2 miles below the outlet of Convict Lake 

 and 1-1/2 miles above the iipper boundary of the 

 Station area . Initial installation was made on 

 June 30, 1925, with flow records beginning on 

 November 15, 1926. 



DISCUSSION OF DATA 



Temperature and flow data presented in this 

 report are for the most part self-explanatory, 

 but a general discussion of the data may be 

 helpful. 



As indicated in table 1, the 13 -year mean 

 water temperature was 47.6° F. The maximum 

 annual mean Was 49.9* F. (1958); the minimum 

 annual mean was 44.7* F. (1952). 



The 13 -year mean air temperature (table 2) 

 was 44.6" F. , three degrees lower than the 13- 

 year mean water temperature (table 1). Maximum 

 annual mean was 47.7° F. (1958); minimum annual 

 mean was 40.7* F. (1952), 



The 13 -year mean of hours below 32* F. 

 was 2,478; greatest number of hours below 

 32° F. was 3,438, in 1952; the least was 2,101 

 in 1958. There are 8,760 hours in a calendar 

 year, except for leap years with 8,736. EXiring 

 this 13 -year period, the leap years were 1952, 

 1956, and 1960. It can be stated that in this 

 general area approximately a third of each year 

 has below-freezing temperatures. 



As indicated in table 3, the 13 -year mean 

 rate of flow was 22.3 c.f .s. Maximum annual 

 mean flow recorded for the period was 34.9 c.f .s. 



