BULLETIN No. 384. 



DECEMBER, I 920 



Meteorological Observations 



MASSACHUSETTS 



AGRICULTURAL EXPERIMENT 



STATION. 



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



Hei,^ht of barometer above ground, 51 ft. Above sea level, syj.^ ft. 

 Height oj Wi7id Instruments 72 ft. Time used, f ^th Mer. 



MONTHLY SUMMARY. 



Pressure. In inches. 

 Maximum reduced to freezing, 30.27, 26th, 9 A 

 Minimum reduced to freezing, 29.04, 2d, 4 A 

 Reduced maximum reading . 30.60, 26ih, 9 a 

 Reduced minimum reading, 29.35, 2d, 4 a 



Mean semi-daily reduced 29.962 



Monthly range 1.25 



*Air Tomperatnre. In Degrees Fahr. 



Highest 58.0, 14th, 6 r 



Lowest 4.0, 26th, 9 A 



Mean hourly 30.7 



Mean of means of max. and min 31,0 



Mean sensible (wet bulb) 26.8 



Monthly range 54.0 



Highest mean daily 45.4. 14th 



Lowest mean daily ii.o, 26th 



Mean maximum 37.9 



Mean minimum 24.1 



Mean daily range 13.8 



Greatest daily range 25.0, 14th 



Least daily range 5.0, 22d 



Humidity. 



Mean dew point 21.5 



Mean force of vapor 166 



Mean relative humidity 73.7 



Precipitation. In inches. 



Total precipitation, in inches 6.02 



Total snow, in inches 7 



Number of days on which .01 inch or more 



rain fell 9 



Days of Sleighing, 5 

 •Temperature in ground shelter. 

 ♦•Reduced to freezing and sea-level. 



Wind. 



Total movement 52S0 m 



Greatest daily movement 419m, 6th 



Least daily movement 22m 13th 



Mean daily movement 170m 



Mean hourly velocity 6.7 m 



Maximum pressure per square foot, io.o,lbs = 



45m per hour, 2d, ip, W.N.W. 

 Maximum velocity for 5 minutes, 32m per 



hour, 2d, 2 p, W.N.W. 

 Prevailing direction, Northw^est. 



Summary. 



North Northeast 13 per cent. 



West Northwest ig 



South Southwest 10 



Northwest 23 



North 13 



Other directions 22 



Weather. 



Mean cloudiness observed .... 57 per cent 

 Total cloudiness recorded by the Sun 



Thermometer . . 140 hours = 49 per cent. 



Number of clear days 5 



Number of fair days 14 



Number of cloudy days 12 



Bright Sunshine. 



Number hours recorded, 143 hrs, = 51 per cent. 

 Rain, ist, 3d, 4th. 5th, loth, 13th, I4tli, 



22d, 23d, 27th. 

 Snow, 5th, 9th, loth, i6th. 22d, 27th. 

 Sleet. 27th. 

 Gales, 45ni. 2d, W.N.W.; 40m, 6th, N.W. 



