BULLETIN No. 379. 



JULY. 1920 



Meteorological Observations 



AT THE 



MASSACHUSETTS 



AGIUCULTUIUL EXPEllIMENT 



STATION. 



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



Height of haro meter above ground, ^T ft. Above sea level, 2YJ.^ ft. 

 Height oj Wind Instruine/its y2 ft. I'ii/ie i/scd, y^th Afer. 



MONTHLY SUMMARY. 



Pressiiie. In inches. 

 Maximum reduced to freezing, 29.95, nth, 8 A 

 Minimum reduced to freezing, 29.23, 24th, 4 a 

 Reduced maximum reading . 30.24, nth, 8 A 

 Reduced minimum reading, 29.52, 24th, 4 A 



Mean semi-daily reduced 29.961 



Montlily range 0.72 



*Air Temperature. In Degrees Fahr. 



Highest S7.5, 13th, 3:30 P 



Lowest 45-0. 26th, 5 A 



Mean hourly 68.3 



Mean of means of max. and niin 68.7 



Mean sensible (wet bulb) 63.7 



Monthly range 42-5 



Highest mean daily 74-4. 13th 



Lowest mean daily 59-7i 26th 



Mean maximum 80.0 



Mean minimum 57-5 



Mean daily range 22.5 



Greatest daily range 36.5,27th 



Least daily range 9-0, 3d 



Humidity. 



Mean dew point 60,9 



Mean force of vapor 686 



Mean relative humidity 77.6 



Precipitation. In inches. 



Total precipitation, in inches 2.06 



Number of days on which .01 inch or more 

 rain fell lo 



•Temperature in ground shelter. 

 ••Reduced to freezing and sea-level. 



Wind. 



Total movement 3S17 m 



Greatest daily movement 239m, 4th 



Least daily movement 33m, 27tli 



Mean daily movement 123m 



Mean hourly velocity 5.1n1 



Maximum pressure per sciuare foot, 7.5 lbs = 



39m per hour, 4th, 4 p, W.N.W. 

 Maximum velocity for 5 minutes, 27m per 



hour, 4th, 2P, W.N.W. 

 Prevailing direction. Southwest. 



Summary. 



South -Southwest 23 per cent 



South 32 ■' " 



Other directions 45 " " 



Weather. 



Mean cloudiness observed .... 50 per cent 

 Total cloudiness recorded by the Sun 



Thermometer . . 140 hours = 30 per cent. 



Number of clear days 15 



Number of fair days 13 



Number of cloudy days .• 3 



Bright Sunshine. 



Number hours recorded, 322 hrs, 70= per cent. 

 Kain. 2d, 3d, 7th. 9th, 12th, 15th, iSth, 



19th, 23d, 24th, 30th, 31st. 

 Thunder and Liiihtninti. 9th. 15th, 20th, 



22d,23d, 24tli, 30th, 31st. 

 Gales. '39m, 4th, W.N.W. 



