FIFTEENTH ANNUAL YEAR BOOK— PART XI 773 



Iowa, and it is believed these conditions were due to the forest fires that 

 prevailed in Arkansas and contiguous territory. 



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

 30.10 inches; the highest recorded was 30.62 inches, at Sioux City, on the 

 19th; the lowest recorded was 29.68 inches, at the same station, on 

 the 14th. 



Temperature. — The monthly mean for the State, 108 stations reporting, 

 was 41.0°, or 6.0° higher than the normal. Only four months of the same 

 name in the last 25 years have been warmer. As compared with the 

 normal the temperature averaged highest in the northwestern part of the 

 State, and lowest in the northeastern, but the difference between the 

 greatest and least departure was not large. The highest monthly mean 

 temperature was 46.2°, at Northboro, Page county, and the lowest was 

 35.4°, at Estherville, Emmet county. The outstanding feature of the tern 

 perature conditions was the sudden and severe cold wave of the 18th-19th. 

 Over large areas the temperature on the 19th was the lowest of record for 

 so early in the season, the readings ranging from 6°, at Keokuk, to — 4° 

 at several stations in northern Iowa. In most cases the monthly highest 

 temperatures at the various stations occurred on the 2d, 3d or 6th, the 

 readings being above 70° except over the extreme northeast part of the 

 State. The highest reported was 80°, at 3 stations. At Des Moines the 

 maximum of 76° on the 2d equaled the highest previous November tem- 

 perature at that station. The weather of Thanksgiving Day (26) de- 

 serves special mention, the day having been remarkably mild and pleasant. 



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

 76 per cent, and 7 p. m. it was 60 per cent. The mean for the month was 

 68 per cent, or about 6 per cent lower than the normal. The highest 

 monthly mean was 81 per cent, at Charles City, and the lowest, 60 per 

 cent, at Sioux City. 



Precipitation. — With the single exception of November, 1904, the cur- 

 rent month was the driest November in the last 25 years. The average 

 precipitation for the State was but 0.22 inch, or 1.29 inches less than the 

 normal. No station had as much as one inch, while at 13 stations only 

 traces occurred. Moreover, at Lake Park, Dickinson county, there was no 

 precipitation whatever. 



The great bulk of the month's supply of moisture came in three periods, 

 viz., those of the 7th-8th, 14th-15th and 29th-30th. The last named period 

 was the most important, being one of general, light, misty rains. The 

 average number of days with 0.01 inch or more precipitation was 2. 



Snowfall. — Some snow fell over much of the State, but only 10 sta- 

 tions reported measurable amounts. The greatest fall was 0.5 inch, at 

 Bedford and Northboro, stations in extreme southwestern Iowa. With 

 the exception of November, 1912, the current November is the only one 

 on record having an average snowfall of only a trace. 



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

 The highest velocity was at the rate of 39 miles an hour from the north- 

 west, at Sioux City on the 18th. The month was not so windy as usual. 



