MOUNT VERNON, ILLINOIS

Average Temperature

Years on Record: 59

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
F		56		32		35		45		55		66		74		78		77		70		58		45		35

Average High Temperature

Years on Record: 59

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
F		67		42		45		56		67		78		87		91		89		83		71		56		44

Average Low Temperature

Years on Record: 60

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
F		45		23		25		34		44		54		62		66		65		58		46		34		26

Highest Recorded Temperature

Years on Record: 65

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
F		114		75		78		92		91		99		105		114		111		105		96		86		74

Lowest Recorded Temperature

Years on Record: 65

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
F		-22		-20		-22		-3		17		29		41		46		44		23		20		-5		---

Average Number of Days Above 90F/32C

Years on Record: 10

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		46		---		---		---		---		1		10		13		14		7		1		---		---

Average Number of Days Below 32F/0C

Years on Record: 10

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		103.3		26		19		16		3		0.3		---		---		---		---		3		15		21

Average Number of Days Below 0F/-17C

Years on Record: 12

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		1.4		0.9		0.4		0.1		---		---		---		---		---		---		---		---		---

Average Precipitation

Years on Record: 66

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
in.		41.6		3.2		2.5		3.9		4		4.2		4.2		3.1		3.8		3.6		3.1		3.1		2.9

Average Precipitable Water

Years on Record: 20

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
in.		0.9		0.4		0.4		0.6		0.7		1		1.3		1.5		1.4		1.1		0.8		0.6		0.5

Average Number of Rainy Days

Years on Record: 66

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		73.8		6.5		5.5		6.8		6.8		6.9		7		5.8		6.5		5.7		5.1		5.1		6.1

Average Snowfall

Years on Record: 61

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
in.		13.8		3.2		4		2.4		0.2		---		---		---		---		---		0.1		0.7		3.2

Average Dew Point

Years on Record: 12

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
F		45		24		28		32		43		54		63		66		66		57		45		32		27

Heating Degree Days

Years on Record: 59

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		4491.5		1007.5		847.5		620		285		---		---		---		---		---		201.5		600		930

Cooling Degree Days

Years on Record: 59

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		1271.5		---		---		---		---		31		285		418.5		372		165		---		---		---

Growing Degree Days

Years on Record: 59

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		3995		---		---		---		165		496		735		883.5		837		615		263.5		---		---

Average Length of Day

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Hours		12.7		10.4		11.3		12.4		13.7		14.8		15.3		15		14.1		12.8		11.6		10.6		10

Average Total Sky Cover

Years on Record: 20

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
%		47		64.5		63.3		56.9		48.9		45.4		33		31.3		28.8		32.2		40.8		55.4		63.7

Average Opaque Sky Cover

Years on Record: 20

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
%		41.3		58.6		57		52.3		42.3		40.6		29.1		24.2		22.3		27.1		35.4		48.6		58.3

Average Wind Speed

Years on Record: 20

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
mph		5.8		6.6		6.5		7		7.5		5.7		5		4.7		4.4		4.3		5.2		6.5		6.3

Average Daily Solar Radiation - Global

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
kWh/m2		4		2		2.8		3.7		4.8		5.5		5.9		6.1		5.4		4.7		3.5		2.2		1.8

Average Daily Solar Radiation - Diffuse

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
kWh/m2		1.6		0.9		1.2		1.6		2		2.3		2.4		2.3		2.1		1.6		1.2		0.9		0.8

Average Daily Solar Radiation - Reflected

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
kWh/m2		4.4		3		3.6		4.3		4.9		5		5.2		5.4		5.2		5.2		4.6		3.3		2.8

Average Daily Solar Radiation - Direct

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
kWh/m2		4.4		3		3.5		4		4.6		4.8		5.3		5.8		5.3		5.4		4.7		3.3		2.8

Maximum Daily Solar Radiation - Global

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
kWh/m2		4		2		2.8		3.7		4.8		5.5		5.9		6.1		5.4		4.7		3.5		2.2		1.8

Maximum Daily Solar Radiation - Diffuse

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
kWh/m2		1.7		0.9		1.2		1.6		2.1		2.4		2.5		2.4		2.2		1.8		1.3		1		0.8

Maximum Daily Solar Radiation - Reflected

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
kWh/m2		5.2		3.9		4.4		5		6		6		5.7		6.1		5.7		6.2		5.4		4.3		3.4

Maximum Daily Solar Radiation - Direct

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
kWh/m2		5.7		4.3		4.8		5		6.6		7		6.3		7.2		6.2		7		5.9		4.7		3.6

Minimum Daily Solar Radiation - Global

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
kWh/m2		3.3		1.6		2.2		2.9		3.8		4.6		4.9		5.6		4.7		3.8		2.7		1.7		1.5

Minimum Daily Solar Radiation - Diffuse

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
kWh/m2		1.5		0.8		1.1		1.5		1.8		2.1		2.3		2.1		1.9		1.4		1.1		0.8		0.8

Minimum Daily Solar Radiation - Reflected

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
kWh/m2		3.5		2.3		2.7		3.2		3.8		4.3		4.4		5		4.5		4.1		3.3		2.2		2.1

Minimum Daily Solar Radiation - Direct

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
kWh/m2		3		2.1		2.3		2.4		2.8		3.5		3.6		4.8		4		3.6		2.8		1.9		1.9