BULLETIN No. 360. 



DECEMBER, 19 18 



Meteorological Observations 



AT THE 



MASSACHUSETTS 



AGRICULTURAL EXPERIMENT 



STATION. 



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



Height of barometer above ground, 5 1 ft- Above sea level, 2yj.^ ft. 

 Height oj Wlfid Instniments y2 ft. Time used, y<jthMer. 



MONTHLY SUMMARY. 



Pressure. In inches. 

 Maximum reduced to freezing, 30.38, 19th, 9 A 

 Minimum reduced to freezing, 29.20, 4th, 12 M 

 Reduced maximum reading . . 30.70, 19th, 9 A 

 Reduced minimum reading, . 29.51, 4th, 12 M 



Mean semi-daily reduced 30-i3o 



Monthly range 1.19 



*Air Temperature. In Degrees Fahr. 



Highest 520, 2ist, 3 p 



Lowest -3.0, 7th, 9 A 



Mean hourly 2S.7 



Mean of means of max. and niin 29.3 



Mean sensible (wet bulb) 26.2 



Monthly range 55-o 



Highest mean daily 46.8, 22d 



Lowest mean daily 12.0, 7th 



Mean maximum 36.5 



Mean minimum 22.0 



Mean daily range 14.5 



Greatest daily range 28.0, 21st 



Least daily range 5.0, 14th, 25th 



Humidity. 



Mean dew point 22.9 



Mean force of vapor 159 



Mean relative humidity . . 84.5 



Precipitation. In inches. 



Total precipitation, in inches 2.95 



Total snow, in inches 7'j 



Number of days on which .01 inch or more 



rain fell 11 



Days of sleighing, 10 



•Temperature in ground shelter. 

 ••Reduced to freezing and sea-level. 



Wind. 



Total movement 3239 m 



Greatest daily movement 348m, ist 



Least daily movement 4m, 20th 



Mean daily movement 104 m 



Mean hourly velocity 4-3 ni 



Maximum pressure per square foot, i r.o lbs = 



49m per hour, ist, 4 A, N.W. 

 Maximum velocity for 5 minutes, 24m per 



hour, ist, I A, W.N.W. 

 Prevailing direction. West Northwest. 



Summary. 



Southwest 10 per cent. 



South Southwest 10 



West Northwest 16 



North 13 



West 10 



Northwest 19 



North Northwest 13 



Other directions 9 



Weather. 



Mean cloudiness observed .... 55 per cent 

 Total cloudiness recorded by the Sun 



Thermometer . .125 hours = 44 per cent 



Number of clear days 11 



Number of fair days 9 



Number of cloudy days 11 



Bright Sunshine. 



Number hours recorded, 158 hrs, = 56 per cent 

 Kain. ist, 6th, nth, 13th, 14th, 15th, 22d, 



24th, 25th. 

 Snow, ist, 3d, 4th, 6th, 7th, nth, 26th, 27th. 



31st. 

 Hail. nth. 

 Gales, 35 miles or more per hour 47 m., 



ist, N.W. 



