BULLETIN No. 341. 



MAY, 1917 



Meteorological Observations 



AT THE 



MASSACHUSETTS 



AGRICULTURAL EXPERIMENT 



STATIOr^. 



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



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

 Height oj Wind Instruments 72 ft. 



MONTHLY SUMMARY. 



Prefssare. In inches. 

 Maximum reduced to freezing, 29.97, 31st, 8 a 

 Minimum reduced to freezing, 29.17, nth, i P 

 Reducedt maximum reading, 30.27, 31st, Sa 

 Reduced! minimum reading, 29.47,11th, IP 



Mean semi-daily reduced 29.809 



Monthly range 0.80 



*Air Temperature. In Degrees Fahr. 



Highest 81.0, 19th, 4:30 P 



Lowest 28.5, 4th, 6 A 



Mean hourly 49.3 



Mean of means of max. and min 49.5 



Mean sensible (wet bulb) 44.4 



Monthly range 52.5 



Highest mean daily 62.7, 19th 



Lowest mean daily , . . . 38.6, 5th 



Mean maximum ^ig.S 



Mean minimum 39.7 



Mean daily range ig.6 



Greatest daily range 37.0, iSth 



Least daily range 5.5,27th 



Humidify. 



Mean dew point 39-2 



Mean force of vapor 357 



Mean relative humidity 70.4 



Wind. 



Total movement 4610 m 



Greatest daily movement 312m, 6th 



Least daily movement i6m, 27th 



Mean daily movement i47 ni 



Mean hourly velocity 6.1 m 



Maximum pressure per square foot, 9.5 lbs = 



44m per hour, 15th, 7 A, N.N.W. 

 Maximum velocity for 5 minutes 27m per 



hour, 12th, 2 p, N.N.W. 

 Prevailing direction, Northwest. 



Precipitation. In inches. 



Total precipitation, in inches 4.13 



Number of days on which .01 incli or more 



rain fell 13 



'Temperature in ground shelter. 

 **Reduced to freezing and sea-level. 



Summary. 



North Northwest 32 per cent 



West Northwest 16 " " 



West 13 " " 



Other directions 39 " " 



Weather. 



Mean cloudiness observed .... 50 per cent 

 Total cloudiness recorded by the Sun 



Thermometer . . 136 hours = 30 per cent 



Number of clear days 14 



Number of fair days 10 



Number of cloudy days 7 



Bright Sunshine. 



Number hours recorded, 317 hrs, = 70 per cent 



Rain, ist, 2d, 4th, 5th, 6th, 9th, loth, 12th, 13th, 

 22d, 23d, 24th, 27th, 2Sth, 29th. 



Snow, 5th. 



Thnnder and Lightning. ?Sth. 



Hail, 5th, I2th. 



Frosts, 4th, i6th, i8th. 



Gales, 35 or more miles per hour. 41m, loth, 

 W.N. W.; 36m, 12th, N.N.W.; 35m, 13th, 

 N.N.W.; 38m, 14th, N.N.W.; 44m. x5th, 

 N.N.W.; 37m, 19th, S.W.; 41m, 25th, N.W.; 

 35m, 26th. W.N.W. 



