BULLETIN No. 390. 



JUNE, 1921 



Meteorological Observations 



AT THE 



MASSACHUSETTS 



AGEICULTUML EXPERIMENT 



STATION. 



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



Height of hiirometgr above-ground, ^i ft. Above sea level, 2yj.^ ft. 

 Height oj Wind Instruments 72 ft. Time used, 1§th Mer. 



MONTHLY SUMMARY. 



Pressure. In inches. 

 Maximum reduced to freezing, 29.98, 5th, 8 A 

 Minimum reduced to freezing, 29.24, 13th, 4 p 

 Reduced maximum reading . 30.27, 5th, 8 A 

 Reduced minimum reading, 29.52, i3tli,4P 



Mean semi-daily reduced 29.942 



Monthly range 0.75 



Air Temperatare. In Degrees Fahr. 



Highest 96.0, 22d, 3 P 



Lowest 40.5, i6th, 5 a 



Mean hourly 66.9 



Mean of means of max. and min 66.4 



Mean sensible (wet bulb) 60.1 



Monthly range 55.5 



Highest mean daily 77.5, 22d 



Lowest mean daily 59.7, 5th 



Mean maximum 79.5 



Mean minimum 53.3 



Mean daily range 26.2 



Greatest daily range 40.0, 22d 



Least daily range 8.5, 28th, 30th 



Humidity. 



Mean dew point 55.8 



Mean force of vapor 655 



Mean relative humidity 70.9 



Precipitation. In inches. 



Total precipitation, in inches 3.87 



Number of days on which .01 inch or more 



rain fell 10 



•Temperature in ground shelter. 

 ••Reduced to freezing and sea-level. 



Wind. 



Total movement 3832 m 



Greatest daily movement 255m, 14th 



Least daily movement 35m 17th 



Mean daily movement 128m 



Mean hourly velocity 5-3 ni 



Maximum pressure per square foot, 7.5 lbs= 



39m per hour, 15th, 3 p, N.W. 

 Maximum velocity iox 5 minutes, 24m per 



hour, 15th, 3 p, N.W. 

 Prevailing direction, West. 



Summary. 



North Northeast 27 per cent 



South Southwest 3° " " 



West 10 " " 



Other directions 33 " " 



Weather. 



Mean cloudiness observed .... 43 per cent 

 Total cloudiness recorded by the Sun 



Thermometer . . 141 hours = 31 per cent. 



Number of clear days 14 



Number of fair days 13 



Number of cloudy days 3 



Bright Sunshine. 



Number hours recorded, 316, = 69per cent. 

 Rain, 3d. 6th, 9th, nth. 13th, 17th, i8th, 23d, 



26th, 27th, 28th, 29th, 30th. 

 Thunder and Liithtnintf. 23d, 26th, 27th, 



29th. 

 Gales, 39ni. 15th., N.W. 



