METEOROLOGICAL OBSERVATORY 



Hatch Experiment Station, 



MASSACHUSETTS AGRICULTURAL COLLEGE, 



Latitude, 42" 28' ■18.5" N. Lonoitiido, 72° 31' 10" W. 



Iloiyht of instruments above ground^ ^1 ft- Above sen level, 200 ft. 



BULLETIN No- 29. 



MAY, 1891. 



MONTHLY SUMMARY. 



VresKure. In inches. 

 Actual m.axiniiiin rcadin.ir, . .30.10, 20tli, 11 A. 

 Actual minimum reading, . . •20..'?7, Ist, 4 a. 



Mean reduced to sea level, 29.983 



Monthly range, . . .79 



*Air Tettipernture. In Degrees F;ihr. 



Highest, 85; S" 



Lowest, .33.; 25. 



Mean, !i7.3; .W.fi 



Monthly Range, r>-2.;r,i. 



Highest mean daily, fiS.9;G9.S 



Lowest mean daily, 40.2; 37. 8 



Mean maximum, (57.5; G9.2 



Mean minimum, 47.7; 42. 



Mean daily range, 20. ; 27.2 



Greatest daily range, 39. ;5L5 



Least daily range .... 5; 10.5 



Humidity. 



Mean dew (loint 44.0 



Mean I'orce of vapor, .5.501 



Mean relative hupiidity, 59.3 



Wind. 



Prevailing Directions. 



North, 22i)ercent. 



South, 15 " " 



South Soutli West, 11 " 



North West 9 " 



Other directions 43 " " 



Total movement 4C10 m. 



Greatest daily movement, . . . . 32fi ta., 17th 



liCast daily movement 42 m., .'50th 



Mean daily movement, 14S.7 ni. 



Mean hourly velocity, G.2 m. 



Maximum pressure per square foot,10!jll)s.= 

 40 m. per hour, 4th, at 4 p. 



* Precipifntion. In inches. 



Total precipitation, 1.04; 1.97 



fVeather. 

 Mean cloudiness observed, . . .54 per cent. 



Numlicr of clear days, 10 



Number of cloudy days 10 



Nunil)er of fair days, 11 



Total cloudiness recorded by the Sun Ther- 

 mometer, 220 hours or .50 per cent. 

 Number of daj'S on which .01 inch or more 



rain fell, 10 



Depth of snow, in inches, on ground at close 

 of month, 



Jirifflit SunshiHe. 



Numlier of Hours recorded, 220.i 



Snow, 5th. 



Total Fall in inches, T. 



K«m, 3d, 4th, 0th, llth, 12th, 1.5th, 10th, 



18th, 21st, 22(1, 20th 2'.ltli, 30th, 31st. 



Frost, 5th, 0th, 7tli, 17th, 19th. 



TUnnder and. Ijiffhtnittfi, . . .llth, 20th. 



Mcfin Osone, 01 jjcr cent. 



Halos. 



Solar 2d, 19th, 20th, 2.5lh, 27th, 2Sth. 



Lunar corona, 21st. 



GnU's, of 40 or more miles per hour, 40,\v.4th ; 



40, \v. .5th; 41, N.W., 17th. 



'The lirst (igures denote readings at top of tower, the second at base. 



