Palestine Exploration Fund - Quarterly Statement for 1894/Meteorological Report from Jerusalem for Year 1885
METEOROLOGICAL REPORT FROM JERUSALEM FOR YEAR 1885.
By James Glaisher, F.R.S.
The numbers in column 1 of this table show the highest reading of the barometer in each month; of these the highest appear in the winter, and the lowest in the summer months; the maximum for the year is 27·616 inches in both January and December. In column 2 the lowest in each month are shown. The minimum, 26·990 inches, is in March. The range of readings in the year is 0·626 inch. The numbers in the 3rd column show the range of readings in each month; the smallest, 0·199 inch, is in June, and the largest, 0·567 inch, is in March. The numbers in the 4th column show the mean monthly pressure of the atmosphere; the highest, 27·467 inches, is in October, and the lowest, 27·257 inches, in August. The mean pressure for the year is 27·374 inches. At Sarona the mean pressure for the year is 29·826 inches.
The highest temperature of the air in each month is shown in column 5. The highest in the year was 98º, on August 7th; on this day the maximum temperature at Sarona was 90°. The first day in the year the temperature reached 90° was on May 18th, and there were two other days in this month when the temperature reached or exceeded 90°. In June there were 3 days, in July, 5 days; in August, 14 days; and in September, 8 days. Therefore the temperature reached or exceeded 90º on 33 days in the year. At Sarona the highest temperature in the year was 103°, on May 23rd; on this day the maximum temperature at Jerusalem was 89°; the first day in the year the temperature reached 90° was on March 16th, and the temperature reached or exceeded 90° on 24 days in the year at Sarona.
The numbers in column 6 show the lowest temperature in each month; the lowest in the year is 34°·5, which occurred on four different nights in the year, viz.: January 7th, March 19th, and December 30th and 31st. The temperature of the air was below 40°, in January, on 10 nights; in February on 3 nights; in March on 2 nights; and in December on 8 nights. Therefore the temperature was below 40° on 23 different nights in the year. The yearly range of temperature was 63°·5. At Sarona the temperature was below 40° on only 3 nights during the year; the lowest in the year, 38°·0, occurred on March 19th. The yearly range of temperature at Sarona was 65°.
The range of temperature in each month is shown in column 7, and these numbers vary from 25°·5 in January, to 49°·5 in March. At Sarona the range of temperature in each month varied from 22° in July, to 52° in March.
The mean of all the highest by day, of the lowest by night, and of the average daily ranges of temperature, are shown in columns 8, 9 and 10 respectively. Of the high day temperatures, the lowest, 50°·8, is in January, and the highest, 89°·3, in August. At Sarona, of the mean of all the highest by day, the lowest, 62°·3, is in January, and the highest, 87º·1, in both August and September,
Of the low night temperature, the coldest, 40°·3, is in January, and the warmest, 62°·6, in July. At Sarona, of the low night temperature, the coldest, 45°·6, is in February, and the warmest, 68°·8, in July. Of the average daily range of temperature, as shown in column 10, the smallest, 10°·5, is in January, and the largest, 27°, in August. At Sarona, of the average daily range of temperature, the smallest, 15°·7, is in January, and the largest, 23°·4, in May.
In column 11 the mean temperature of each month is shown, as found from observations of the maximum and minimum thermometers only. The month of the lowest temperature is January, 45°·5, and that of the highest, October, 79°·3. The mean for the year is 63°·7. At Sarona the lowest in the year was January, 54°·4, and that of the highest August, 77°·7. The mean for the year at Sarona was 65°·9.
The numbers in columns 12 and 13 are the monthly means of a dry and wet bulb-thermometer, taken daily at 9 a.m., and in column 14 the monthly temperature of the dew-point, or that temperature at which dew would have been deposited at the same hour is shown; the elastic force of vapour is shown in column 15. In column 16 the water present in a cubic foot of air is shown; in January and February was as small as 3 grains, and in July as large as 512 grains. In column 17 the additional weight required for saturation is shown. The numbers in column 18 show the degree of humidity, saturation being considered 100; the smallest number indicating the driest month is 42, in May, and the largest, 86, in January. The weight of a cubic foot of air under its pressure, temperature, and humidity, at 9 a.m., is shown in column 19.
The most prevalent winds in January were E. and S.W., and the least prevalent were N. and S.E. In February the most prevalent was S.W., and the least were N. and S. In March the most prevalent were S.E. and W., and the least were N.E. and N.W. In April the most prevalent was N.W., and the least were N. and S. In May the most prevalent were N.W., E., and W., and the least was S.W. In June and July the most prevalent were N.W. and S. W., and the least were N.E. and S. In August and September the most prevalent was N.W., and the least were S.E. and S. In October the most prevalent were N.E. and N.W., and the least was S. In November the most prevalent were N.W. and S.E., and the least were S.W. and W.; and in December the most prevalent winds were N.E. and W., and the least prevalent wind was N. The most prevalent wind for the year was N.W., which occurred on 98 times during the year, of which 21 were in July, 14 in August, and 13 in September; and the least prevalent wind was S., which occurred on only 15 times during the year, of which 4 were in January, and 3 in both November and December. At Sarona the most prevalent wind for the year was W., which occurred on 69 times during the year, and the least prevalent wind was E., which occurred on only 7 times during the year.
The numbers in column 28 show the mean amount of cloud at 9 a.m.; the month with the smallest amount is August, and the largest, January, Of the cumulus, or fine weather cloud, there were 58 instances in the year, of which 14 were in July and 11 in September. Of the nimbus, or rain cloud, there were 41 instances in the year, of which 13 were in January and 9 in March, and only one from May to October. Of the cirrus there were 2 instances; of the cirro cumulus, 31 instances; of the cirro stratus, 42 instances; of the cumulus stratus, 58 instances; and 133 instances of cloudless skies, of which 28 were in August, 17 in September, and 16 in July. At Sarona there were 103 instances of cloudless skies, of which 14 were in November, and 13 in August.
The largest fall of rain for the month in the year was 779 inches, in January, of which 2·25 inches fell on the 25th. The next largest fall for the month was 6·27 inches in December, of which 1·42 inch fell on the 25th, 1·40 inch on the 27th, and 1·37 inch on the 24th. No rain fell from June 11th to October 5th, making a period of 116 consecutive days without rain. The fall of rain for the year was 29·47 inches, which fell on 58 days during the year. At Sarona the largest fall of rain for the month in the year was 7·89 inches in January. No rain fell at Sarona from June 11th to October 5th, making a period of 116 consecutive days without rain. The fall of rain for the year was 20-06 inches, which fell on 63 days.