Number of days with thunderstorms in a month in Boulder, CO
YearJANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDECYEAR
19710004716136430053
197200106171312710057
197300026816156000 53
19740010211189420047
197510004101411410045
1976000291012 14700054
19770006101119123000 61
1978001286972000 35
197900005616124000 43
19800012951771000 42
19810000121113179000 62
19820011121313167210 66
1983012051618135110 62
199000136718151100061
1991001114171716600072
199200219121816210061
19930002148913600052
19940004991315721060
1995000213148111000058
1996000031511141110055
199700008191321410066
199800217101214710054
19990000991314400049
2000000333917410040
20010023571815810059
20020000510312610037
2003000101013116200052
200400126141712920063
20050002615119510049
200600007815124000 46
200700111148111562059
2008000035 5114 2 0 0 30
200900016 171510600055
20100002491010110037
2011000338207211149
20120004311164400042
201300104101516720063
2014000110111211311023
201500021315
1971-96 average0.100.100.501.608.2011.1014.3012.605.800.700.200.00
1971-96 std0.200.200.701.603.503.803.303.202.800.90.400.00
1981-2010 average0.000.040.541.637.4011.4612.4213.36.371.000.210.00
1981-2010 std0.000.200.782.143.684.114.173.193.281.29.510.00

Thuderstorm data for 1971-present excludes the years 1984-1989 (not currently available). Data was taken by a different person for the time periods 1971-1983 and 1990-present. Days are 5pm MST to 5pm MST for 1990 to present and midnight-midnight for 1971-1983.