METEOROLOGICAL OBSERVATORY 



OK THE 



Hatch Experiment Station 



MASSACHUSETTS AGRICULTURAL COLLEGE 



Latitude, 42° 23' 48.5" N. Longitude 72° 31' 10" \V. 



Height of barometer above ground, 51 ft- Above sea level, 2"/^.^ ft. 

 Height of Wind Instruments 72 ft. 



BULLETIN No. 204. 



DECEMBER, 1905. 



MONTHLY SUMMARY. 



Pressure. In inches. 

 Maximum reduced to freezing, 30.54. ist, 11 A. 

 Minimum reduced to freezing. 29.03, agtli, 5 p. 

 Reducedt maximum reading, 30.86, 1st, 11 a. 

 Reducedt minimum reading, 29.33, 29th, 5 p. 



Mean semi-daily reduced, 3o-o7S 



Monthly range, 1-53 



*Air Temperature. In Degrees Fahr. 



Highest, 54-5, Sth, 3 p. 



Lowest, 3-0. nth, 5 A. 



Mean hourly, 29.8 



Mean of means of max. and min., .... 30.1 



Mean sensible (wet bulb), 26.9 



Monthly range, 51.5 



Highest mean daily, 44.3,3d 



Lowest mean daily, ii.S, 15th 



Mean maximum, 38. 9 



Mean minimum, 21.3 



Mean daily range, 17.6 



Greatest daily range, 31.5, iSth 



Least daily range, 6.0, 3oth 



Huniiditif. 



Mean dew point, 23.8 



Mean force of vapor, 165 



Mean relative humidity, S0.6 



frecipitation. In inclies. 



Total precipitation, 3.1 



Number of days on which .01 inch or more 



rain or melted snow fell 8 



Total snow in inches, 



Snow on ground at end of month, . . . none 



* Temperature in ground shelter. 

 1 Reduced to freezing and sea-level. 



Wind. 



Total movement, 4051 m. 



Greatest daily movement, .... 320 m., loth 



Least daily movement 6 m., 19th 



Mean daily movement, ....... 131 m. 



Mean hourly velocity, 5-5 ni. 



Maximum pressure per square foot, 14.0 lbs.= 



53 m. per hour, 30th, 11 A., W. 

 Prevailing Direction, Northwest. 

 Summary. 



Northwest, 17 percent. 



West, Northwest, 10 " " 



South, Southwest, 10 " " 



Southeast, 10 " " 



East, 13 " " 



North, Northeast, 10 " " 



Other directions, 31 " " 



Weather. 



Mean cloudiness observed, . . . .56 per cent. 

 Total cloudiness recorded by the Sun Ther- 

 mometer, i55hrs.=55 per cent. 



Number of clear days, 10 



Number of fair days, 8 



Number of cloudy days, 13 



Jiright Sunshine. 



Number of hours recorded, . . 128 hrs.=451t 

 Itain, 2d, 3d, 20th, 2ist. 22d, 23d, 29th. 

 Qdles, 2i miles or more per hour, 35 m. loth, 

 N.W.; 3;m. 24th,, W.N. \V.; 53m., 30th, W. 

 Snoiv, 2d, 9th, loth, nth, 30th. 

 Days of Sleighing, 2 



