NINETEENTH ANNUAL YEAR BOOK— PART X 531 



unprecedented so late in the season, though a snowstorm of slightly less 

 intensity occurred in south-central Iowa on April 7, 1917. 



All vegetation made slow progress. Spring seeded grains depended 

 largely on subsoil moisture till the middle of the month after which tem- 

 peratures were too low, so that germination was very uneven; some that 

 was seeded more than a month before was scarcely showing green at the 

 end of the month over much of the State. Pears and plums were in full 

 bloom in the southern counties near the close of the month. Field work 

 progressed rapidly with the soil in excellent condition. Eighty-five per 

 cent of the corn ground was made ready for the planter and a little 

 planting was done in the south. Seed corn is generally scarce and of low 

 vitality. Winter wheat, pastures and meadows suffered from drouth, cold 

 and high winds. 



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

 30.01 inches. The highest recorded was 30.78 inches, at Dubuque, on the 

 9th, and the lowest was 29.23 inches at Charles City, on the 29th. The 

 monthly range was 1.55 inches. 



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

 records of 106 stations, was 44.8°, or 3.9° lower than the normal. By 

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

 follows: Northern, 43.5°, or 3.2° lower than the normal; Central, 45.0°, or 

 3 9° lower than the normal; Southern 45.9°, or 4.7° lower than the normal. 

 The highest monthly mean was 47.6°, at Northboro, and the lowest was 

 41.5% at Decorah. The highest temperature reported was 79°, at Corydon 

 and Fayette, on the 1st, and the lowest was 12° at Lake Park, on the 8th. 

 The temperature range for the State was 67°. 



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

 72 per cent; and at 7 p. m. it was 53 per cent. The mean for the month 

 was 62 per cent, or about 5 per cent below the normal. The highest 

 monthly mean was 74 per cent, at Charles City, and the lowest was 62 

 per cent, at Sioux City. 



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

 records of 113 stations, was 2.32 inches, or 0.54 inch less than the normal. 

 By divisions the averages were as follows: Northern, 1.93 inches, or 0.75 

 inch less than the normal; Central, 2.31 inches, or 0.55 inch less than the 

 normal; Southern. 2.32 inches, or 0.54 inch less than the normal. The 

 greatest amount, 4.20 inches, occurred at Olin, and the least, 1.01 inches, 

 •at Humboldt. The greatest amount in any 24 consecutive hours, 1.80 

 inches, occurred at Lamoni on the 21st. 



Snoivfall. The average snowfall for the State was 3.5 inches, or 1.7 

 inches more than the normal. The averages by divisions were: Northern, 

 1.0 inch; Central, 2.5 inches; Southern, 7.0 inches. The greatest amount, 

 24.0 inches, occurred at Bedford. 



Wi7id. The prevailing direction of the wind was from the northeast. 

 The highest velocity reported from a regular Weather Bureau station was 

 at the rate of 59 miles an hour from the northwest at Sioux City on the 

 29th. 



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

 •of sunshine was 60. or about normal. The per cent of the possible amount 

 1 



