METEOROLOaiCAL OBSERVATORY 



OF THE 



Hatch Experiment Station 



MASSACHUSETTS AGRICULTURAL COLLEGE, 



^ft^ivmEi^sx. 



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



Height of barometer above ground^ 5^ ft- Above sea level, 2^3.5 ft. 

 Height of Wind Instrume/its 72 ft. 



BULLETIN No. 209. 



MAY. 1906. 



MONTHLY SUMMARY. 



fressure. In inches. 

 Maximum reduced to freezing, 30.19, i5th,SA. 

 Minimum reduced to freezing, 29.11,3d, 4 a. 

 Reducedt maximum reading, 30.49, 15th, 8 a. 

 Reducedt minimum reading, 29.41,3d, 4 a 



Mean semi-daily reduced, 29.962 



Monthly range i.oS 



*A.ir Tetnperature. In Degrees Fahr. 



Highest, 90-0, i8th, 3 p. 



Lowest, 31.5,4th, 6 A. nth, 5 A. 



Mean hourly, 56-7 



Mean of means of max. and min 56.9 



Mean sensible (wet bulb), 51.3 



Monthly range 58.5 



Highest mean daily 74.8,18th 



Lowest mean daily, 42.0, loth 



Mean maximum, 69.5 



Mean minimum, 44-4 



Mean daily range 25.1 



Greatest daily range, 41.5, '6th 



I-east daily range, 3.0, 28th 



HiiiHiditi/. 



Mean dew point, 46.4 



Mean force of vapor 478 



Mean relative humidity, 70.9 



Precipitation. In inches. 



Total precipitation, 4.95 



Number of days on which .01 inch or more 

 rain or melted snow fell, 12 



* Temperature in ground shelter, 

 t Reduced to freezing and sea-level. 



Wind. 



•I'otal movement, 3766 m. 



Greatest daily movement, . . • . 320 m., 13th 



Least daily movement, i m., 6th 



Mean daily movement, 121 m. 



Mean hourly velocity, 5 rn- 



Maximum pressure per square foot, 7.5 lbs.= 



39 m. per hour, 29th, 10 A., N.N.W. 

 Maximum velocity for 5 minutes, 30 m. per 



hour 3d, 10 A., E.N.E. 

 Prevailing Direction, West, Southwest. 



Summary. 

 South, Southeast, 23 per cent. 



West 13 ;; ;; 



West, Northwest ^3 [[ " 



Northwest, 13 " 



North, Northwest, 10 " " 



Other directions, 28 " 



Weather. 

 Mean cloudiness observed, . • . .47 per cent. 

 Total cloudiness recorded by the Sun Ther- 

 mometer, 165 hrs.=36 per cent. 



Number of clear days 14 



Number of fair days, 12 



Number of cloudy days 5 



Bright Sunshine. 



Number of hours recorded, . . 288 hrs.=64* 

 Bain, 2d, 3d, 5th, 6th, 7th, 9th, 17th, 19th, 



24th, 25d, 27th, 2Sth, 29th. 

 Oales, 35 miles or more per hour, 3s ni. 3d, 



E.; 35m. 19th, W.N.W.; 36 m. 20th, N.; 



39 m. 29th, N.N.W. 



Bail, 2d. 



Thunder and Ziightning, 17th, i8th, 19th, 



24th, 25th. 

 Frosts, 4th, nth, 15th, 21st, 20th. 

 Killing Frost, nth. 



