BULLETIN No. 269. 



MAY, 1911 



Meteorological Observations 



AT THE 



MASSACHUSETTS 



AGRICULTURAL EXPERIMENT 



STATIOIM . 



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



Height of barometer above ground, 31 ft. Above sea level, 2^3.^ ft. 

 Height of Wind Itistruments 72 ft. 



MONTHLY SUMMARY. 



Pressure. In inches. 



Maxuuuni reduced to freezing, 30 1 1, 14th, 8 A, 

 Minimiuii reduced to freezing, 29.13, 2d, 1:30 A. 

 Reduced I niaxi mum reading, 30.40, 14th, 8 A. 

 Reducedt minimum reading, 29.43, 2d, 1:30 A. 



Mean semi-daily reduced, 3o-034 



Monthly range, 0.97 



*Air Temperature. In Degrees Fahr. 



Highest 94-5. 22d, 2:30 p. 



Lowest, 27.0, 4th, 4:3oA. 



Mean hourly, 6i-9 



Mean of means of max. and min 62.5 



Mean sensible (wet bulb), 560 



Monthly range, 67.5 



Highest mean daily 76-2, 22d 



Lowest mean daily, 37-6, 3d. 



Mean maximum 75-6 



Mean minimum, 49-4 



Mean daily range, 26.2 



Greatest daily range 42.5. 7t*i 



Least daily range, 5-5. 24th 



Humirtity. 



Mean dew point, 5i-7 



Mean force of vapor, 563 



Mean relative humidity, ....••• -72.2 



Precipitation. In inches. 



Total precipitation, i-37 



Number of days on which .01 incli or more 



rain fell ' ^ 



♦Temperature in ground shelter. 

 t Raduced to freezing and sea-level. 



Wind. 



Total movement, 4939m 



Greatest daily movement, .... 46oni., 3d 



Least daily movement, 62m., 30th 



Mean daily movement, i59.3 m 



Mean hourly velocity, 6.6 m 



Maximum pressure per square foot, 7.5 Ibs.= 

 39m. per hour, 3d, 11 A., W.N.W. 



Maximum velocity for 5 minutes, 36ni. per 

 hour 3d, 5?., W.N.W. 



Prevailing Direction, South. 



Summary. 



South 29 percent. 



South Southeast 13 " 



West Northwest 10 " 



West 10 " 



East Northeast ig " 



Other directions 2S " 



Weather. 



Mean cloudiness observed, .... 55 per cent. 

 Total cloudiness recorded by the Sun Ther- 

 mometer i33hrs.=39 per cent. 



Number of clear days, 14 



Number of fair days, 12 



Number of cloudy days, 5 



Bright Sunshine. 



Number of hours recorded, . . 320 l)rs.=6i^ 

 Rain, ist, 2d, 12th, 18th, 19th. 20th, 24th, 

 25th, 31st. 

 Frosts, 4th, 5th. 



Tliunder and Lightning, ist,2d, 12th, iSth, 

 19th, 25th. 



Gales, 35 or more miles per hour : 35m, 2d, 

 W.N.W.; 39m, 3d, W.N.W. 



