FIFTEENTH ANNUAL YEAR BOOK— PART XI 761 



Temperature. — The monthly mean temperature for the State, as shown 

 by the records of 111 stations, was 62.2°, or 1.7° above the normal. This 

 has been exceeded but five times during the past 25 years. The first 17 

 days were unusually cool, and light frost and freezing temperatures oc- 

 curred on several dates in many localities. The 2d, 8th, 12th, 13th and 

 15th were the coldest days; the lowest reading, 25° being recorded on the 

 13th at Washta. After the 17th the temperature was above the normal 

 most of the time, and the excess for the month was made up during 

 this period. Tlie highest temperature was recorded at most stations on 

 the 26th; the highest reading being 96° at Cedar Rapids. 



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

 74 per cent, and at 7 p. m. 54 per cent. The mean for the month was 

 64 per cent, or about 4 per cent less than the normal. The greatest 

 monthly mean was 73 per cent at Charles City, and the least, 60 per cent 

 at Davenport. 



The average for the State, 118 stations reporting, was 3.31 inches, or 

 1.26 inches less than the normal. By sections the averages were as 

 follows: Northern, 4.44 inches, or 0:04 inch less than the normal; Cen- 

 tral, 3.52 inches, or 1.07 inches less than the normal; Southern, 1.96 

 inches, or 2.68 inches less than the normal. All of the rain came in the 

 form of local showers, many of them being excessive. At Des Moines, on 

 the lOth-llth, 2.58 inches fell in 3 hours and 19 minutes; on the 10th 

 1.22 inches fell in 24 minutes; on the 11th 1.20 inches fell in 18 minutes; 

 and on the 23d, 1.31 Inches fell in 29 minutes. 



Precipitation. — The rainfall was light over the southern three tiers of 

 counties, except over small areas in Jefferson and Madison counties, where 

 heavy local showers occurred which did more harm than good. Over nine 

 counties extending from Montgomery and Page eastward to Lucas and 

 Decatur the rainfall was decidedly deficient, and within that area all 

 crops, except corn, suffered from the lack of moisture. A few flakes of 

 snow fell at Algona and Britt on the 7th. Measurable precipitation oc- 

 curred on an average of 10 days. 



Wind. — The prevailing direction of the wind was from the south. The 

 highest velocity recorded was 50 miles per hour, from the north, at 

 Sioux City, on the 23d. Wind squalls occurred on several dates, and 

 were destructive in many localities. The squalls accompanied severe 

 electrical storms and were attended in many cases by hail. 



Sunshine and Cloudiness. — The average duration of sunshine was 

 about 71 per cent, or about 8 per cent more than the normal. The aver- 

 age number of clear days was 14; partly cloudy, 11; cloudy, 6. 



Thunderstorms occurred on the 3d, 4th, 6th, 9th, 10th, 11th, 20th, 22d, 

 23d, 24th, 25th, 26th, 27th, 28th, 29th and 31st. 



Hail occurred on the 3d, 7th, 10th and 11th. 



Rivers. — There has been no "Spring Rise" in the rivers of this section 

 this year, but there has been a fair boating stage throughout the month. 



