Page:VCH Hertfordshire 1.djvu/78

 A HISTORY OF HERTFORDSHIRE TABLE VII MEAN RAINFALL IN EACH DISTRICT, WITH ITS RELATION TO COUNTY MEAN River District 1860-69 1870-79 1880-89 1890-99 inches per cent. inches per cent. inches per cent. inches per cent. Cam
 * Rhee . ..

23-47 IO 23'55 -16 23.50 - 12 22-37 IO Ivel Hiz. . . . 23-89 -9 25-61 -8 25-27 -5 23-61 -5 Thame : Up. Thame

26-10 + 5 r Bulbourne 29-2O + 12 31-00 + ii 29-60 + IO 25-94 + 5 Gade. . . 26'29 + I 28-59 + 2 28-46 + 6 25-87 + 5 Colne{ Ver ... 27-45 + 5 29-56 + 6 28-44 + 6 26-35 + 6 1 Upper Colne.

24-64 = v. Lower Colne.

27-63 i 30-98 + 16 26-54 + 7 ' Mimram

25-58 -4 23-82 -4 Beane.

26-25 -6

24-61 /-,_, Rib ....

25-04 -6 24-22 2 Lita Ash ....

26-24 -6 25-98 -3 24-82 = Upper Lea. . 25-OI -4 27-10 -3 24-69 -8 23-11 -7 ^ Lower Lea.

2 7 - 7 8 + 4 23-65 -5 During the last half-century there have been falls of rain of at least z inches in twenty-four hours on twelve occasions. On the lath of July, 1889, such a fall occurred at eighteen stations out of thirty then recording, and at least 3! inches at four of these. Falls of at least 3 inches have occurred on seven occasions, and of at least 3! inches on 30th June, 1878 ; I2th July, 1889, the day with the greatest average rainfall at all stations ; and iyth July, 1890, the day with the greatest fall of rain at any one station, viz. 4' 19 inches at Moor Park, Rick- mansworth. Two other elements of climate, viz., sunshine and wind, remain for consideration, but can only be very briefly noticed. The following are averages for the twelve years 1887-98 for wind at Berkhamsted, St. Albans, and Bennington, and for sunshine at Berkhamsted only. The prevailing direction of the wind is from S.W. (sixty-one days in the year) to W. (sixty-two days), and the next most frequent winds are N. to N.E. and S. (each about thirty-seven days). The least frequent are S.E. (twenty-five days). About forty-four days in the year are re- corded as calm. March is the most windy month, June the calmest. The duration of bright sunshine is least in December and greatest in May; December having rather more than an hour a day, and May nearly six and a half hours. Throughout the year the sun shines brightly for nearly four hours a day. 40