MOUNT HAMILTON.

[Lick Observatory.]

The director of the Lick Observatory, Dr. Wallace W. Campbell, has kindly placed at the disposal of the Weather Bureau the observations made at Mount Hamilton by different members of the observatory staff from 1888 to 1900. The following named gentlemen have at various times acted as observers: Charles B. Hill, A. J. Burnham, H. K. Curtis, A. O. Leuschner, A. L. Colton, C. D. Perrine, R. G. Aitken, W. H. Wright, H. K. Palmer, E. F. Coddington, and A. J. Cloud.

The observatory is situated on Mount Hamilton, a peak in the Coast Range, in Santa Clara County. The elevation of the station is 1,283 meters (4,209 feet) above sea level. The observatory is situated in latitude 37° 20′ 25.6" north, longitude 121° 38′ 4.22" west. The mountain is about 14 miles in an air line directly east of the city of San Jose.

The records for temperature at Mount Hamilton cover a period of twelve years and for precipitation twenty years. The mean annual temperature is 52°. The coldest month is January, with a mean temperature of 39.7°, and the warmest month is July, with a mean temperature of 69.4°. The highest temperature recorded is 94°, on July 1, 1891, and the lowest 13°, on February 4, 1899.

Rain falls in every month of the year, but in July and August the showers are light and infrequent. The mean annual precipitation is 32 inches, which, it is interesting to notice, is more than double that of San Jose, where the mean, based upon records covering twenty-six years, is but 14.88 inches. The ratio of the rainfall on the mountain to that in the valley appears to be fairly constant for all months in the year. December is the month of heaviest precipitation on the mountain. More than half of the annual rainfall occurs in the four months of December, January, February, and March. The annual precipitation has exceeded 30 inches during eight years of the twenty, and has fallen below 20 inches during two years. These dry years were 1885, when the rainfall amounted to but 18.23 inches, and the memorable 1898, when but 17.11 inches fell. The years of maximum rainfall were 1884, when 90.12 inches fell, and 1894, when 44.49 inches fell.

1883.

1884.

1885.

1.99

1886.

4.40

1887..

1888.

1889.

1.04

1.92

3.21

1890.

7.93

6.60 4.39 1.79

1891.

1.38

7.12 4.10. 3.08.

3.10 3.75 8.66 2.66 7.55 0.00 0.00 0.00 0.65 2.15
5.60 12.76 16.35 11.96 1.24 3.85 0.00 0.15 0.65 3.71
0.57 1.15 2.08 0.16 0.36 0.00 0.00 0.15
0.05 1.92
1.80 5.77 6.79. 0.70 0.00 0.00 0.00 0.00 0.60 2.82
2.83 7.80 1.39 5.75 0.25 0.30 0.04 0.001
0.33 0.09 0.90
10.04 1.38
3.40 0.68 1.25 0.67 0.00 0.02 0.49 0.03
1.42 6.17
0.05 0.00 0.00 0.00 4.38 4.46
2.42 0.00 0.00. 0.00 0.80 0.02 0.58
1.01 0.57 0.00 0.00
0.38
3.52 0.32 0.00
T.
0.95
0.16 0.00 0.00 0.48
2.78 0.64 0.02
T. 1.64 2.98
10.00 3.08 1.46 2.30 2.39 0.00 0.01 0.00 0.08 0.78 2.46 3.16
6.70 2.10 0.02
T. 0.28 0.47 1.85 5.86 4.91
0.00 0.00 0.07 1.25 1.51 2.70
0.00 0.00 0.29 1.33 1.23. 2.13
0.00 0.12
0.01 0.02
T.

NOTE.-November 16-17, 1893, maximum hourly velocity, 80 miles; velocity of gusts probably over 100 miles. January 15, 1895, highest hourly velocity (estimated), 80 to 90 miles.

LOCAL CLIMATOLOGY.

APTOS.

[Data from records of Southern Pacific Railway Company.]

Aptos is situated in Santa Cruz County, on Monterey Bay, about 7 miles southeast of the city of Santa Cruz, in latitude 36° 58′ north, longitude 121° 54' west; elevation 102 feet above sea level.

The mean annual temperature, based upon records covering sixteen years, is 56, which is practically the same as that of San Francisco, and 2.4° lower than the annual mean at Santa Cruz. June, July, and August are the warmest months, with mean temperatures of 62.5°, 62.3°, and 61.4°, respectively; September is also a warm month, with a mean of 60.9°. The coldest month is January, with a mean of 48.5°; the means for February and December are nearly the same. The maximum seldom exceeds 90°, the highest recorded in recent years being 91°, in June, 1898. Minimum temperatures of 26° are recorded in January, 1898, December, 1900, and February, 1901.

The average annual precipitation during the past sixteen years is 25.63 inches, about 1 inch less than that of Santa Cruz. The greatest precipitation occurs in December and January, but heavy rains also fall in November, February, and March. The rainfall during June, July, August, and September is very light and infrequent. During the month of December, 1889, the rainfall was 18.29 inches, and the total of that year was 37.94 inches.

MONTHLY AND ANNUAL MEAN TEMPERATURE (DEGREES FAHRENHEIT).

Year.

Jan. Feb. Mar. Apr.

May. June. July. Aug. Sept. Oct. Nov. Dec. Annual.

1885.

1886.

1887.

1888.

1889.

48.6

51.6 56.6 59.7

59.6

1890.

46.2

49.0 53.6 56.2

61.0

61.9

49.2 51.1 55.4 57.7 61.7 65.4 64.9 63.5 60.2 59.3 56.0 53.7
51.0 54.8 52.3 56.6 59.3 58.9 61.4 61.9 60.9 55.1 51.6
49.1 47.0 55.5 55.7 58.9 63.4 61.0 60.1 60.1
46.0 51.9 53.0 58.4 59.7 67.9 65.9 63.2 61.8
62.5
63.4
61.9
62.0 62.6 61.2

58.2

52.3 54.6 60.2 62.7 60.3 54.0 52.7 45.8 44.6
72.7 63.6 60.8 64.1 59.5 51.1 48.1
48.7 50.4 44.9 55.4 62.6 60.9 59.8 58.81 58.1. 50.8
51.8 47.4 51.6 56.2 55.0 59.9
58.9 60.3 58.0 54.8 53.0 49.7
59.6 59.0 60.7
62.5
61.4

52.3

56.6

44.9

54.4

54.7

60.2

59.6 55.2 49.3

55.7

62.3

60.9 57.8 53.0 49.7

56.0

123

Year.

MONTHLY AND ANNUAL PRECIPITATION (INCHES AND HUNDREDTHS).

Jan. Feb. Mar. Apr. May. June. July. Aug. Sept. Oct. Nov. Dec. Annual.

1885.

1886.

1887.

1888.

1889.

1890.

10.29

1891.

1.08

1892.

0.92

1893.

3.40

1894.

7.56

6.05

1895.

2.86 0.19 0.43 1.78 0.13 0.00 0.18 0.00 0.07 0.02 10.65 3.83
7.61 0.80 4.09 7.10 0.27 0.00 0.00 0.00 0.00 0.70 0.84 1.53
0.95 8.82 0.76 1.61 0.19 0.00
0.00 0.00 0.47 0.05 1.11
5.85 1.59 5.32 9.50 0.79 0.25 0.00 0.00 0.45 0.00 5.75
0.50 0.87 5.90! 0.85 1.71 0.00
0.00
0.00 7.49 2.33
4.60 3.16 1.25 1.66. 0.00
0.00 0.40 9.40 0.28 2.93
13.16 3.01 2.84 0.20 0.00 0.00 0.00 1.00 0.07 0.27 7.64
4.90 2.67 1.95 2.47 0.00 0.00 0.00 0.65 1.36 3.66
3.41 7.97 1.54
0.42 0.00 0.00 0.00 0.22 0.33 3.16
0.92 0.89 2.50 0.24 0.00 0.00 2.00 2.93 0.71 13.32
1.88 1.39 0.00
0.00 0.00 0.00
5.01 1.59 0.00 0.00 0.76 0.26 1.64 5.92
6.27 4.03
0.00 0.30
0.10 0.00 0.00 0.00 1.69 0.82 1.39
1.17 0.32 1.17 0.20 0.00 0.00
1.40 0.76 0.75 1.84
6.43
0.22 13.14 1.25 1.00 0.00 0.00 0.00 0.00 6.01 4.24 4.36
4.56 0.53 2.19 1.53 0.59 0.00 0.00 0.00 0.27 1.58 8.95 1.82
4.75 3.62 3.78
1.89! 1.02 0.05 0.01 0.05 0.45 1.57 3.19 5.25

Auburn is the county seat of Placer County, a narrow county in the central eastern portion of California, extending from Lake Tahoe and the Nevada line westward to Sutter County and the southern portion of Nevada County, and is situated in latitude 38° 54' north, longitude 121° 50′ west, a short distance southwest of the junction of the middle and north forks of the American River. The elevation is 1,360 feet, with the land sloping eastward to the American River, where the elevation of the channel is about 500 feet. The Sierra Nevada Mountains, running through the eastern portion of the county, reach an elevation of 7,000 feet. The foothills are excellent fruit-growing districts.

The general movement of the air is from the north, northwest, and northeast. The date of the last killing frost in the spring of 1899 was May 2, and the first in autumn, 1899, was October 15. The mean annual temperature, based upon records covering a period of twenty-nine years, is 60.1°. The coldest month is January, with a mean temperature of 45.5°, and the warmest is July, with a mean temperature of 76.7°. During the months of June, July, August, and September the mean temperature exceeds 70°.

The highest temperature recorded within a period of twenty-two years was 110°, which occurred during the months of July and August, 1898. The lowest temperature recorded was 12, in January, 1888. Reliable frost data are not available.

The mean annual rainfall for twenty-nine years is 33.58 inches. Two-thirds of this rainfall occurs between December and April. Rain seldom falls during July or August. The rainfall has exceeded 40 inches during six years of the twenty-nine, and in 1884 exceeded 50 inches. There have been but two years in the past twenty-nine when the rainfall did not reach 20 inches, viz., 1877, when but 18.07 inches fell, and 1898, when 19.96 inches fell.