DECATUR, ILLINOIS

Average Temperature

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
C		11.5		-2.6		-0.6		5.3		11.6		17.1		22.3		24.3		23.1		19.2		12.5		6.1		-0.7

Average High Temperature

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
C		17.1		1.8		4		10.8		17.7		23.4		28.1		30.3		29.1		25.9		18.8		10.9		3.8

Average Low Temperature

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
C		5.9		-7		-5.1		-0.1		5.4		10.8		16.4		18.3		17.1		12.4		6.1		1.2		-5.1

Highest Recorded Temperature

Years on Record: 67

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
C		45		22		23		31		34		38		40		45		41		40		35		28		21

Lowest Recorded Temperature

Years on Record: 66

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
C		-31		-30		-31		-22		-9		-3		---		7		4		-6		-11		-19		-28

Average Number of Days Above 90F/32C

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		20.3		---		---		---		---		0.7		3.8		8.5		5.1		1.9		0.3		---		---

Average Number of Days Above 80F/26C

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		99		---		---		0.2		1.4		8.2		20		27.8		24.9		12.9		3.6		---		---

Average Number of Days Above 70F/21C

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		161.9		---		---		2.2		10		21.9		28.6		31		30.4		26.2		9.9		1.6		0.2

Average Number of Days Above 60F/15C

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		210.3		0.5		1.1		8.6		19.2		29		30		31		31		29.8		21.4		7.8		0.8

Average Number of Days Above 50F/10C

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		253.7		3.3		4.8		15.3		26.2		31		30		31		31		30		29.7		15.9		5.4

Average Number of Days Above 40F/4C

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		301.3		9.8		12.4		25.7		29.5		31		30		31		31		30		31		25.5		14.5

Average Number of Days Below 70F/21C

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		348.7		31		28		31		29.9		30.4		26.2		24.5		26.1		29.6		30.9		30		31

Average Number of Days Below 60F/15C

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		287.7		31		28		30.9		28.8		26.3		12.6		6.3		11		22.4		29.5		30		31

Average Number of Days Below 50F/10C

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		221.8		30.8		27.9		29.2		24.2		14.4		2.2		0.2		0.5		8.5		25.1		28		30.8

Average Number of Days Below 40F/4C

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		164.9		30.3		27.3		25.5		13.3		2.9		0.1		---		---		0.7		12.9		22.4		29.5

Average Number of Days Below 32F/0C

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		113.4		26.8		23.5		16.6		5		0.3		---		---		---		---		2.9		13.8		24.5

Average Number of Days Below 20F/-6C

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		42.6		15.5		9.9		3.4		0.1		---		---		---		---		---		---		1.6		12

Average Number of Days Below 10F/-12C

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		14.2		6.9		3		0.1		---		---		---		---		---		---		---		---		4.2

Average Number of Days Below 0F/-17C

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		2.8		1.7		0.2		---		---		---		---		---		---		---		---		---		0.9

Average Precipitation

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
mm		977.9		43.2		50.8		66		96.5		109.2		111.8		99.1		94		73.7		83.8		86.4		63.5

Average Precipitable Water

Years on Record: 20

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
cm.		2		1		1		1.3		1.7		2.4		3.1		3.5		3.4		2.7		1.9		1.4		1.1

Average Number of Rainy Days

Years on Record: 73

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		67		5		4		6		6		6		6		5		5		5		4		4		4

Average Snowfall

Years on Record: 64

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
cm		51		12		12		10		1		---		---		---		---		---		---		3		10

Average Dew Point

Years on Record: 12

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
C		5		-6		-3		-1		4		10		15		18		17		12		6		---		-4

Heating Degree Days

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		5522		1168		950		727		379		141		17		1		5		67		345		663		1058

Cooling Degree Days

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		1049		---		---		1		13		73		229		333		269		111		19		---		---

Growing Degree Days

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		3538		2		3		43		168		401		663		798		730		495		186		44		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		10.2		11.2		12.5		13.8		14.9		15.5		15.2		14.1		12.9		11.6		10.5		9.9

Average Total Sky Cover

Years on Record: 20

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
%		52.4		64.9		62.7		57.3		54.9		54		47.2		43.8		41.1		38		46.2		56.3		63.7

Average Opaque Sky Cover

Years on Record: 20

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
%		48.8		62.3		59.3		54.6		51.1		48.8		42.3		37		35.8		35.2		42.8		53.7		61.3

Average Wind Speed

Years on Record: 20

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
km/h		15.8		18.8		18.5		18.9		19.5		16.1		13		11.7		10.8		11.7		15		17.8		17.5

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		6.8		9.4		12.9		16.6		19.5		21.6		22.1		19		16.2		11.6		7.2		5.7

Average Daily Solar Radiation - Diffuse

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		5.6		2.8		3.9		5.5		7.1		8.2		8.7		8.1		7.3		5.6		4.2		3.1		2.5

Average Daily Solar Radiation - Reflected

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		15.5		11.4		12.9		15.2		16.8		17.9		18.8		19.7		18.6		18.3		15.7		11		9.8

Average Daily Solar Radiation - Direct

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		15.6		11.4		12.7		14.2		15.8		17.6		19.7		21.5		18.9		19		15.9		11		9.8

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		6.8		9.4		12.9		16.6		19.5		21.6		22.1		19		16.2		11.6		7.2		5.7

Maximum Daily Solar Radiation - Diffuse

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		5.9		2.9		4		5.6		7.3		8.6		9.1		8.8		7.6		6.2		4.5		3.2		2.6

Maximum Daily Solar Radiation - Reflected

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		18.8		14.1		16.7		19.1		19.7		22.7		21.5		21.9		20.1		22.3		18.4		16.7		12.5

Maximum Daily Solar Radiation - Direct

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		21.2		14.8		17.8		20.3		20.8		27.7		26		26.5		21.9		26		19.9		19		13.4

Minimum Daily Solar Radiation - Global

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		11.3		5.5		7.6		9.6		13.5		15.8		19		16.9		17.2		12.7		8.8		4.2		4.6

Minimum Daily Solar Radiation - Diffuse

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		5.1		2.7		3.6		4.9		6.6		7		8		7.5		7		4.6		3.8		2.6		2.4

Minimum Daily Solar Radiation - Reflected

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		11.8		8.2		9.9		10.6		13.4		14.5		16.7		15.1		16.7		13.7		11		5.4		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		7.5		8.4		7.8		10.3		11.3		15.3		12.5		15.5		11.7		9.3		3.8		6.2