NINETEENTH ANNUAL YEAR BOOK— PART X 555 



Pressure. The mean pressure (reduced to sea level) for the State 

 was 30.02 inches. The highest pressure recorded was 30.31 inches, at 

 Dubuque on the 12th, and the lowest was 29.65 at Sioux City on the 3d. 

 The monthly range was 0.66 of an inch. 



Temperature. The mean temperature for the State, as shown by the rec- 

 ords of 100 stations, was 73.1°, or 1.0° lower than the normal. By 

 divisions, three tiers of counties to the division, the means were as fol- 

 lows: Northern, 71.2° or 1.5° lower than the normal; Central, 73.0° or 1.3° 

 lower than the normal; Southern, 75.0°, or 0.2° lower than the normal. 

 The highest monthly mean was 78.0° at Corning, and the lowest was 68.6°, 

 at Postville. The highest temperature reported was 105°, at Clarinda, on 

 the 28th; the lowest was 40°, at Audubon, on the 1st. The temperature 

 range for the State was 65°. 



Humidity. The average relative humidity for the State at 7 a. m. was 

 77 per cent, and at 7 p. m. it was 56 per cent. The mean for the State 

 was 66 per cent, or 1 per cent lower than the normal. The highest 

 monthly mean was 74 per cent, at Sioux City, and the lowest was 58 per 

 cent at Omaha, Nebr. 



Precipitation. The average precipitation for the State, as shown by the 

 records of 108 stations, was 3.17 inches, or 0.79 inch less than the normal. 

 By divisions the averages were as follows: Northern, 4.57 inches, or 0.69 

 inch more than the normal; Central, 3.00 inches, or 0.96 inch less than 

 the normal; Southern, 1.93 inches, or 2.09 inches less than the normal. 

 The greatest amount, 8.05 inches, occurred at Postville, and the least 0.26 

 of an inch at Albia. The greatest amount in 24 consecutive hours, 3.62 

 Inches, occurred at Charles City on the 25th and 26th. 



Wind. The prevailing direction of the wind was from the southeast. 

 The highest velocity reported from a regular "Weather Bureau station was 

 41 miles an hour, from the south, at Sioux City, on the 3d. 



Sunshine and Cloudiness. The average per cent of the possible amount 

 of sunshine was 72, or 2 per cent less than the normal. The per cent of 

 the possible amount at the regular Weather Bureau stations was as fol- 

 lows: Charles City, 65; Davenport, 73; Des Moines, 78; Dubuque, 74; 

 Keokuk, 80; Sioux City, 64; Omaha, Nebr., 71. 



Miscellaneous Phenomena. Aurora, lOth. Fog, 5th, 6th, 15th, 16th, 17th, 

 25th. Hail, Northern Division, 22d, 25th, 26th; Southern Division, 27th, 

 28th. Halo (lunar 22d; solar 1st, 14th, 16th, 17th, 27th). Rainbow (lunar), 

 at Grinnell on the 25th. Thunderstorms, 2d, 3d, 4th, 5th, 6th, 7th, 9th, 14th, 

 15th, 19th, 21st, 22d, 23d, 24th, 25th, 26th, 27th, 28th, 29th, 31st. Tornado, 

 14th. 



Rivers. The principal rivers fell steadily during the month except 

 when affected temporarily by heavy rainfall. Moderate stages for July 

 prevailed on the Missouri and low stages on the Mississippi. None of the 

 streams in the interior of the State were overflowed and low stages pre- 

 vailed generally. 



