JOLIET, ILLINOIS

Average Temperature

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
F		49.4		21.7		26.9		37.2		48.2		59.6		69.8		73.7		71.6		64.5		52.7		39.9		27.4

Average High Temperature

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
F		59.6		29.9		35.2		46.8		59.5		71.6		81.3		84.6		82.4		76		64.1		48.3		35.2

Average Low Temperature

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
F		39.2		13.5		18.6		27.6		36.9		47.5		58.2		62.8		60.7		52.9		41.2		31.4		19.5

Highest Recorded Temperature

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
F		89.3		41.9		45.3		56.2		67.5		81.9		87.5		89.3		88		83.6		71.9		57.9		44.8

Lowest Recorded Temperature

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
F		-1.1		-1.1		3.7		21		32		42.2		52.2		58.9		53.4		49.1		35.2		21.3		6.3

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
in		37		1.6		1.6		2.5		3.8		3.9		4.2		4.3		3.8		3.1		2.7		3		2.4

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
in		17.4		3.4		5.6		4.6		7.4		7.6		11.7		17.4		10.1		10.8		8.4		8.2		7.3

Least Reported Precipitation in a Month

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
in		---		---		---		0.4		0.5		0.7		0.4		0.1		0.5		---		0.4		0.5		0.3

Most Precipitation Reported in a Day

Years on Record: 82

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
in		6.9		2.7		2.3		3.1		3.5		2.5		6.9		5.4		3.3		5.3		5		1.8		3

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		65.1		4.2		4.1		6.1		6.8		6.7		7.1		6.7		6.2		5		4.1		3.5		4.6

Average Snowfall

Years on Record: 82

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
in		24.7		6.4		5.5		3.9		0.5		---		---		---		---		---		0.2		2.7		5.5

Most Snow Reported in a Month

Years on Record: 82

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
in		21.9		21.5		17.8		12.8		6		---		---		---		---		---		3		17.3		21.9

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
F		41		20		20		29		38		47		59		62		62		53		44		30		22

Heating Degree Days

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		6464		1343		1067		863		505		230		32		4		20		86		391		755		1168

Cooling Degree Days

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		809		---		---		---		2		61		174		272		223		70		7		---		---

Growing Degree Days

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		2814.6		---		---		---		---		297.6		594		734.7		669.6		435		83.7		---		---

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
kWh/m2		3.9		1.8		2.6		3.6		4.6		5.5		6.1		6.1		5.3		4.3		3		1.8		1.5

Average Daily Solar Radiation - Diffuse

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
kWh/m2		1.5		0.7		1		1.4		1.9		2.3		2.4		2.3		2		1.5		1.1		0.8		0.6

Average Daily Solar Radiation - Reflected

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
kWh/m2		4.3		3.2		3.9		4.4		4.7		5.1		5.3		5.5		5.3		4.9		4.1		2.9		2.9

Average Daily Solar Radiation - Direct

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
kWh/m2		4.5		3.2		3.9		4.3		4.6		5.2		5.8		6.1		5.6		5.1		4.1		2.9		2.9

Maximum Daily Solar Radiation - Global

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
kWh/m2		3.9		1.8		2.6		3.6		4.6		5.5		6.1		6.1		5.3		4.3		3		1.8		1.5

Maximum Daily Solar Radiation - Diffuse

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
kWh/m2		1.6		0.7		1.1		1.5		2		2.4		2.5		2.4		2.1		1.7		1.2		0.8		0.7

Maximum Daily Solar Radiation - Reflected

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
kWh/m2		5.3		4.1		4.6		5.8		5.6		6.4		6.1		6		6		6		4.8		4.1		3.8

Maximum Daily Solar Radiation - Direct

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
kWh/m2		6.1		4.4		4.9		6.5		6.2		8		7.7		7.4		7		7		5.1		4.5		4.2

Minimum Daily Solar Radiation - Global

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
kWh/m2		3.1		1.5		2.1		3		3.6		4.4		5.2		4.9		4.7		3.3		2.4		1.2		1.2

Minimum Daily Solar Radiation - Diffuse

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
kWh/m2		1.3		0.7		0.9		1.2		1.8		1.9		2.1		2.1		1.8		1.3		1.1		0.7		0.6

Minimum Daily Solar Radiation - Reflected

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
kWh/m2		3.4		2.4		2.9		3.5		3.6		4		4.5		4.3		4.6		3.6		3.1		1.7		2

Minimum Daily Solar Radiation - Direct

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
kWh/m2		2.9		2.2		2.6		3		2.7		3.2		4.1		3.8		4.3		3.1		2.8		1.3		1.9