ESRL : PSD : Boulder Monthly Thunderstorms

Days with thunderstorms per month in Boulder
Year	JAN	FEB	MAR	APR	MAY	JUN	JUL	AUG	SEP	OCT	NOV	DEC	YEAR
1971	0	0	0	4	7	16	13	6	4	3	0	0	53
1972	0	0	1	0	6	17	13	12	7	1	0	0	57
1973	0	0	0	2	6	8	16	15	6	0	0	0	53
1974	0	0	1	0	2	11	18	9	4	2	0	0	47
1975	1	0	0	0	4	10	14	11	4	1	0	0	45
1976	0	0	0	2	9	10	12	14	7	0	0	0	54
1977	0	0	0	6	10	11	19	12	3	0	0	0	61
1978	0	0	1	2	8	6	9	7	2	0	0	0	35
1979	0	0	0	0	5	6	16	12	4	0	0	0	43
1980	0	0	1	2	9	5	17	7	1	0	0	0	42
1981	0	0	0	0	12	11	13	17	9	0	0	0	62
1982	0	0	1	1	12	13	13	16	7	2	1	0	66
1983	0	1	2	0	5	16	18	13	5	1	1	0	62
1990	0	0	1	3	6	7	18	15	11	0	0	0	61
1991	0	0	1	1	14	17	17	16	6	0	0	0	72
1992	0	0	2	1	9	12	18	16	2	1	0	0	61
1993	0	0	0	2	14	8	9	13	6	0	0	0	52
1994	0	0	0	4	9	9	13	15	7	2	1	0	60
1995	0	0	0	2	13	14	8	11	10	0	0	0	58
1996	0	0	0	0	3	15	11	14	11	1	0	0	55
1997	0	0	0	0	8	19	13	21	4	1	0	0	66
1998	0	0	2	1	7	10	12	14	7	1	0	0	54
1999	0	0	0	0	9	9	13	14	4	0	0	0	49
2000	0	0	0	3	3	3	9	17	4	1	0	0	40
2001	0	0	2	3	5	7	18	15	8	1	0	0	59
2002	0	0	0	0	5	10	3	12	6	1	0	0	37
2003	0	0	0	10	10	13	11	6	2	0	0	0	52
2004	0	0	1	2	6	14	17	12	9	2	0	0	63
2005	0	0	0	2	6	15	11	9	5	1	0	0	49
2006	0	0	0	0	7	8	15	12	4	0	0	0	46
2007	0	0	1	1	1	14	8	11	15	6	2	0	59
2008	0	0	0	0	3	5	5	11	4	2	0	0	30
2009	0	0	0	1	6	17	15	10	6	0	0	0	55
2010	0	0	0	2	4	9	10	10	1	1	0	0	37
2011	0	0	0	3	3	8	20	7	2	1	1	1	49
2012	0	0	0	4	3	11	16	4	4	0		0
2013	0	0	1	0									0.27
1990-2002 average	0.0	0.0	0.5	1.3	7.8	10.5	11.8	14.8	6.8	.7	0.08	0.0	54.4
1990-1996 std	0.0	0.0	0.9	1.1	3.3	3.9	4.5	2.0	3.2	0.8	.4	0.0	X
1971-96 average	0.1	0.1	0.5	1.6	8.2	11.1	14.3	12.6	5.8	0.7	0.2	0.0	X
1971-96 std	.2	.2	0.7	1.6	3.5	3.8	3.3	3.2	2.8	0.9	.4	0.0	X

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.

Physical Sciences Division