JOLIET, ILLINOIS

Average Temperature

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
C		9.7		-5.7		-2.8		2.9		9		15.3		21		23.2		22		18.1		11.5		4.4		-2.6

Average High Temperature

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
C		15.3		-1.2		1.8		8.2		15.3		22		27.4		29.2		28		24.4		17.8		9.1		1.8

Average Low Temperature

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
C		4		-10.3		-7.4		-2.4		2.7		8.6		14.6		17.1		15.9		11.6		5.1		-0.3		-6.9

Highest Recorded Temperature

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
C		31.8		5.5		7.4		13.4		19.7		27.7		30.8		31.8		31.1		28.7		22.2		14.4		7.1

Lowest Recorded Temperature

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
C		-18.4		-18.4		-15.7		-6.1		---		5.7		11.2		14.9		11.9		9.5		1.8		-5.9		-14.3

Average Number of Days Above 90F/32C

Years on Record: 82

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		30.4		---		---		---		---		1.2		7.3		9.8		7.7		4		0.3		---		---

Average Number of Days Below 32F/0C

Years on Record: 82

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		129.7		28.5		25.5		22.1		6.9		0.6		---		---		---		0.2		3.6		16.5		25.7

Average Number of Days Below 0F/-17C

Years on Record: 82

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		10.3		4.9		2.7		0.2		---		---		---		---		---		---		---		0.1		2.4

Average Precipitation

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
mm		939		40		42		62		95		98		107		110		97		80		69		76		62

Average Number of Days With Precipitation

Years on Record: 82

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		108		9		8		10		11		11		10		8		8		8		8		8		9

Most Reported Precipitation in a Month

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
mm		441		86		142		118		187		194		297		441		255		274		214		208		185

Least Reported Precipitation in a Month

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
mm		---		1		---		10		14		17		10		3		12		1		11		13		7

Most Precipitation Reported in a Day

Years on Record: 82

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
mm		174.2		69.1		59.4		79.8		88.9		63.8		174.2		136.4		83.3		135.1		127.5		44.5		76

Avg. No. of Days w/Precip. Above 0.2in/5mm

Years on Record: 82

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		67		4		4		6		7		8		7		6		5		6		5		5		4

Avg. # of Days w/Precip. Above 0.4in/10mm

Years on Record: 82

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		21		1		1		2		2		2		3		2		2		2		2		1		1

Avg. No. of Days w/Precip. Above 1in/25mm

Years on Record: 82

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

Average Number of Rainy Days

Years on Record: 19

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		65		4		4		6		6		6		7		6		6		5		4		3		4

Average Snowfall

Years on Record: 82

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
cm		62.7		16.3		14		9.9		1.3		---		---		---		---		---		0.5		6.9		14

Most Snow Reported in a Month

Years on Record: 82

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
cm		55.6		54.6		45.2		32.5		15.2		---		---		---		---		---		7.6		43.9		55.6

Average Relative Humidity

Years on Record: 8

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
%		74		80		77		76		70		70		72		71		74		74		71		76		80

Average Dew Point

Years on Record: 8

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
C		5		-6		-6		-1		3		8		15		16		16		11		6		-1		-5

Heating Degree Days

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		3591.1		746.1		592.8		479.4		280.6		127.8		17.8		2.2		11.1		47.8		217.2		419.4		648.9

Cooling Degree Days

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		449.4		---		---		---		1.1		33.9		96.7		151.1		123.9		38.9		3.9		---		---

Growing Degree Days

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		1563.7		---		---		---		---		165.3		330		408.2		372		241.7		46.5		---		---

Average Length of Day

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Hours		12.7		10.1		11.1		12.5		13.9		15.1		15.7		15.4		14.3		12.9		11.5		10.3		9.7

Average Daily Solar Radiation - Global

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		13.9		6.3		9.4		13.1		16.6		19.8		22		22.1		19.2		15.4		10.7		6.5		5.5

Average Daily Solar Radiation - Diffuse

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		5.4		2.6		3.6		5.2		6.9		8.1		8.6		8.1		7.1		5.5		4.1		2.9		2.2

Average Daily Solar Radiation - Reflected

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		15.6		11.4		13.9		15.9		17		18.2		19.1		19.7		18.9		17.7		14.8		10.4		10.4

Average Daily Solar Radiation - Direct

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		16.1		11.4		14		15.6		16.5		18.6		20.9		21.9		20		18.3		14.8		10.4		10.6

Maximum Daily Solar Radiation - Global

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		13.9		6.3		9.4		13.1		16.6		19.8		22		22.1		19.2		15.4		10.7		6.5		5.5

Maximum Daily Solar Radiation - Diffuse

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		5.7		2.6		3.8		5.4		7.2		8.5		9		8.8		7.5		6		4.3		3		2.3

Maximum Daily Solar Radiation - Reflected

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		19		14.8		16.5		20.8		20.3		22.9		22		21.7		21.5		21.7		17.2		14.8		13.8

Maximum Daily Solar Radiation - Direct

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		21.9		15.8		17.5		23.4		22.3		28.8		27.7		26.7		25.1		25.1		18.3		16.3		15.2

Minimum Daily Solar Radiation - Global

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		11.2		5.3		7.7		10.9		12.8		15.7		18.6		17.5		16.9		12		8.7		4.4		4.4

Minimum Daily Solar Radiation - Diffuse

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		4.8		2.3		3.4		4.4		6.3		6.8		7.7		7.5		6.4		4.6		3.8		2.6		2

Minimum Daily Solar Radiation - Reflected

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		12.1		8.6		10.3		12.7		12.8		14.4		16.3		15.6		16.5		13		11.3		6		7.3

Minimum Daily Solar Radiation - Direct

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		10.5		7.9		9.5		10.9		9.8		11.5		14.8		13.7		15.5		11.1		10		4.8		6.7