Palestine Exploration Fund - Quarterly Statement for 1894/Meteorological Report from Jerusalem for 1884
METEOROLOGICAL REPORT FROM JERUSALEM FOR YEAR 1884.
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 27·668 inches in January. In column 2 the lowest in each month are shown; the minimum is 26·997 inches in April. The range of readings in the year was 0·671 inch. The numbers in the 3rd column show the extreme range of readings in each month; the smallest, 0·144 inch, is in August, and the largest, 0·531 inch, in January. The numbers in the 4th column show the mean monthly pressure of the atmosphere; the highest, 27·486 inches, is in December, and the lowest, 27·285 inches, in July. The mean pressure for the year was 27·380 inches; at Sarona the mean pressure for the year was 29·859 inches.
The highest temperature of the air in each month is shown in column 5. The highest in the year was 105° on both the 6th and 9th of August; at Sarona the maximum temperature on these days was 88° and 89° respectively. The first day in the year the temperature reached 90° was on May 29th, and the temperature reached or exceeded 90° on two other days in this month. In June there were 8 days when the temperature reached or exceeded 90°; in July, on 7 days; in August, on 10 days; in September, on 1 day; and in October, on 4 days. Therefore the temperature reached or exceeded 90° on 33 days in the year. At Sarona the temperature reached 90° as early as April 13th, and reached or exceeded 90° on only 14 days in the year; the highest in the year at Sarona, viz., 100°, took place on October 16th; on this day the maximum temperature at Jerusalem was 90°·5.
The lowest temperature of the air in each month is shown in column 6. The lowest in the year was 28°·5, on January 23rd; the temperature was below 40°, in January, on 22 nights; in February it was below 40° on 20 nights; and in March, on 8 nights. Therefore the temperature was below 40° on 50 nights in the year. The yearly range of temperature was 76°·5. At Sarona the temperature was below 40° on only 9 nights in the year; the lowest temperature in the year was 32°, on January 22nd and 24th. The yearly range at Sarona was 68°.
The range of temperature in each month is shown in column 7, and these numbers vary from 23°·5 in February, to 50° in both May and August. At Sarona the range of temperature in each month varied from 24° in February to 51° 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, 49°·4, is in January, and the highest, 88°, in August. At Sarona, of the high day temperatures, the lowest, 60°·2, is in January, and the highest, 86°, in August.
Of the low night temperatures, the coldest, 38°·0, is in January, and the warmest, 63°·5, in August. At Sarona, of the low night temperatures, the coldest, 40°·9, is in January, and the warmest, 68°·9, in August.
The average daily range of temperature, as shown in column 10, the smallest, 11°, is in February, and the largest, 24°·5, is in August. At Sarona, the average daily range, the smallest, 14°·l, is in February, and the largest, 24°·4, in April.
In column 11, the mean temperature of each month, as found from observations of the maximum and minimum thermometers only, are shown; the month of the lowest temperature is January, 43°·7, and that of the highest, August, 75°·8. The mean for the year is 61°·6. At Sarona, the mean temperature of each month, the lowest is January, 50°·5, and that of the highest August, 77°·4. The mean for the year at Sarona is 65°·7.
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 of the temperature at which dew would have been deposited. The elastic force of vapour is shown in column 15, and in column 16 the water present in a cubic foot of air, in January and February, was as small as 2·8 grains, and as large as 5 grains in August. The numbers in column 18 show the degree of humidity, saturation being considered as 100; the smallest number in this column is in June, and the largest number is in January and February. 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 wind in January was S.W., and the least prevalent winds were N., N.E., and E. In February the most prevalent were S.W. and W., and the least were N., S., and N.W. In March the most prevalent was S.W., and the least were N.E. and S. In April the most prevalent were S.W., W., and S.E., and the least were N. and N.E. In May the most prevalent were N.W. and S.E., and the least were N. and S. In June the most prevalent were N.W. and W., and the least were S. and N. In July the most prevalent was N.W., and the least were E. and S. In August the most prevalent were N.W. and W., and the least S. and S.W. In September the most prevalent was N.W., and the least were E. and S. In October the most prevalent were N.W., E., and N., and the least was N.E. In November the most prevalent were S. and W., and the least was N.; and in December the most prevalent wind was E., and the least prevalent were S. and W. The most prevalent wind for the year was N.W., which occurred on 85 times during the year, of which 16 were in July, 12 in August, and 11 in September; and the least prevalent wind for the year was S., which occurred on only 19 times in the year, of which 8 were in November. At Sarona the most prevalent wind for the year was S.W., which occurred on 72 times during the year, and the least prevalent wind was E., which occurred on only 8 times during the year.
The numbers in column 28 show the mean amount of cloud in each month; the month with the smallest amount is July, and the largest, February. Of the cumulus, or fine weather cloud, there were 63 instances, of which 15 were in September. Of the nimbus, or rain cloud, there were 46 instances, of which 14 were in February, and 9 in both January and March. Of the cirrus there were 3 instances; of the stratus, 2 instances; of the cumulus stratus, 64 instances; of the cirro stratus, 16 instances; of the cirro cumulus, 54 instances; and 118 instances of cloudless skies, of which 21 were in July, 20 in June, and 15 in August, and 3 only in February. At Sarona there were 74 instances of cloudless skies, of these 16 were in June, 12 in December and 11 in November.
The largest fall of rain for the month in the year was in February, 8·26 inches, of which 1·24 inch fell on the 14th, and 1·22 inch fell on the 9th. The next largest fall for the month was 6·09 inches in January, of which 2·83 inches fell on the 22nd, 1·24 inch on the 21st, and 1·05 inch on the 20th. No rain fell from May 5th to October 30th, making a period of 177 consecutive days without rain. The total fall of rain for the year was 23·96 inches, which fell on 54 days during the year. At Sarona the largest fall of rain for the month in the year was 6·69 inches in January, and the next in order was 6·09 inches in February. No rain fell from May 5th to October 20th, with the exception of June 23rd, when 0·02 inch fell, making a period of 167 consecutive days without rain. At Sarona the total fall for the year was 18·73 inches, which fell on 65 days during the year.