MOUNT VERNON, ILLINOIS

Average Temperature

Years on Record: 59

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
C		13		---		2		7		12		18		23		25		24		21		14		7		1

Average High Temperature

Years on Record: 59

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
C		19		5		7		13		19		25		30		32		31		28		21		13		6

Average Low Temperature

Years on Record: 60

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
C		7		-5		-3		1		6		12		16		18		18		14		7		1		-3

Highest Recorded Temperature

Years on Record: 65

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
C		45		23		25		33		32		37		40		45		43		40		35		30		23

Lowest Recorded Temperature

Years on Record: 65

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
C		-30		-28		-30		-19		-8		-1		5		7		6		-5		-6		-20		---

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		26		19		16		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		---		---		---		---		---		---		---		---		---		---		---		---

Average Precipitation

Years on Record: 66

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
mm		1050		80		60		90		100		100		100		70		90		90		70		70		70

Average Precipitable Water

Years on Record: 20

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
cm.		2.2		1.1		1.1		1.4		1.8		2.6		3.3		3.8		3.6		2.9		2.1		1.5		1.2

Average Number of Rainy Days

Years on Record: 66

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		73		6		5		6		6		6		7		5		6		5		5		5		6

Average Snowfall

Years on Record: 61

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
cm		35		8		10		6		---		---		---		---		---		---		---		1		8

Average Dew Point

Years on Record: 12

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
C		7		-4		-2		---		6		12		17		18		18		13		7		---		-2

Heating Degree Days

Years on Record: 59

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		2908.4		559.7		470.8		344.4		158.3		---		---		---		---		---		111.9		333.3		516.7

Cooling Degree Days

Years on Record: 59

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		706.4		---		---		---		---		17.2		158.3		232.5		206.7		91.7		---		---		---

Growing Degree Days

Years on Record: 59

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		2219.5		---		---		---		91.7		275.6		408.3		490.8		465		341.7		146.4		---		---

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
km/h		9.4		10.6		10.4		11.3		12.1		9.2		8.1		7.5		7		6.8		8.3		10.4		10.1

Average Daily Solar Radiation - Global

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		14.5		7.1		9.9		13.4		17.3		19.6		21.4		22		19.4		16.9		12.5		8		6.3

Average Daily Solar Radiation - Diffuse

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		5.8		3.1		4.2		5.7		7.2		8.3		8.8		8.3		7.4		5.8		4.3		3.3		2.8

Average Daily Solar Radiation - Reflected

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		15.8		10.9		12.9		15.4		17.5		18		18.7		19.6		18.8		18.8		16.6		11.9		10.1

Average Daily Solar Radiation - Direct

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		15.8		10.8		12.7		14.3		16.6		17.4		19.1		20.9		19		19.5		16.9		12		10

Maximum Daily Solar Radiation - Global

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		14.5		7.1		9.9		13.4		17.3		19.6		21.4		22		19.4		16.9		12.5		8		6.3

Maximum Daily Solar Radiation - Diffuse

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		6		3.2		4.3		5.8		7.5		8.6		9.1		8.7		7.8		6.3		4.7		3.4		2.8

Maximum Daily Solar Radiation - Reflected

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		18.6		14.2		15.9		17.8		21.5		21.7		20.4		21.9		20.6		22.1		19.5		15.4		12.1

Maximum Daily Solar Radiation - Direct

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		20.6		15.5		17.2		17.9		23.8		25.2		22.8		26		22.5		25.3		21.4		17.1		12.8

Minimum Daily Solar Radiation - Global

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		12		5.9		8		10.4		13.6		16.7		17.8		20		17		13.8		9.6		6		5.2

Minimum Daily Solar Radiation - Diffuse

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		5.3		2.9		3.9		5.4		6.4		7.5		8.4		7.6		7		4.9		3.9		3		2.7

Minimum Daily Solar Radiation - Reflected

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		12.6		8.4		9.8		11.4		13.5		15.3		15.7		17.9		16.3		14.8		11.8		7.9		7.7

Minimum Daily Solar Radiation - Direct

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		10.7		7.4		8.4		8.6		10.2		12.4		13.1		17.3		14.5		13		10		6.7		6.9