BULLETIN No. 252. 



DECEMBER, 1909 



Meteorological Observations 



AT THE 



MASSACHUSETTS 



AGKICULTURAL EXPERIMENT 



STATION. 



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



Height of barometer above ground, 51 ft' Above sea level, 2jj.^ ft. 

 Height of Wind Instruments 72 ft. 



MONTHLY SUMMARY. 



fressure. In inches. 



Maximum reduced to freezing, 30.26, t2th, 12 p. 

 Minimuin reduced to freezing, 28.72, 26th, 6 A. 

 Reducedt maximum reading, 30. sS, 12th, 12 p 

 Keducedt minimum reading, . 29.04, 26th, 6 A 



Mean semi-daily reduced, 29.S8S 



Monthly range 1.54 



*Air Teinperntare. In Degrees Fahr. 



Highest 51.5,5th, 3 p. 



Lowest, —8.5,30th, 8 a- 



Mean hourly, 24.7 



Mean of means of max. and min 25.5 



Mean sensible (wet bulb), 21.0 



Monthly range, 60.0 



Higliest mean daily 39.3,14th 



Lowest mean daily 2.6, 30th 



Mean maximum, 33.1 



Mean minimum, 17.S 



Mean daily range 15.3 



Greatest daily range 28.0, 31st 



Least daily range, 4.5, 26th 



Humid ity. 



Mean dew point 15.8 



Mean force of vapor, 131 



Mean relative humidity, 75.2 



freclpitation. In inches. 



Total precipitation, 2.95 



Number of days on which .01 inch or more 



rain or melted snow fell • 5 



Total snow in inches 12 



Wind. 



Total movement, 5S45ni. 



Greatest daily movement, .... 507m., 26th. 



Least daily movement, 37ni., 2Sth. 



Mean daily movement 189m. 



Mean hourly velocity, 7.9 m. 



Maximum pressure per square foot, 14.0 lbs.= 



53m. per hour, 26th, 7 a., N.N.E. 

 Maximum velocity for 5 minutes, 33ni. per 



hour 13th, 10 P., S.E. 

 Prevailing Direction, North. 

 Summary. 



North Northeast 26 percent 



North Northwest 19 " " 



West Northwest 16 " " 



North 13 " " 



Northwest 10 " " 



Northeast 10 " " 



Other directions, 6 " " 



Weather. 

 Mean cloudiness observed, .... 45 per cent. 

 Total cloudiness recorded by the Sun Tlier- 



niometer, 135 hrs.=48 per cent. 



Number of clear days, 8 



Number of fair days, 16 



Number of cloudy days, 7 



Bright Sunshine. 

 Number of hours recorded, . . 14S hrs. = 529S 

 Kaiu, 7th, 13th, 14th. 

 Snow, Sth, 13th, i6th, 22d, 25th, 26th. 

 Hail, 7th, 13th. 

 Days Sleighing, 6. 



Gale8, 35 miles or more per hour; 42m. 

 13th, S.E.; 37m. 14th, S. S. E.; 53m. 26th, 

 N.N.E. 



* Temperature in ground shelter, 

 t Reduced to freezing and sea-level. 



