RESTON, VIRGINIA

Average Temperature

Years on Record: 48

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
C		12.4		0.1		1.4		6.5		12		17		21.9		24.4		23.8		19.7		12.9		7.7		2.2

Average High Temperature

Years on Record: 48

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
C		18.6		5.2		7		12.7		18.9		23.7		28.3		30.7		30		26.1		19.8		13.8		7.4

Average Low Temperature

Years on Record: 48

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
C		6.3		-5.1		-4.3		0.2		5.2		10.4		15.6		18.3		17.6		13.3		6.2		1.5		-3.1

Highest Recorded Temperature

Years on Record: 48

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
C		40		23.9		26.1		31.7		33.9		36.1		37.8		40		40		37.2		34.4		28.9		26.1

Lowest Recorded Temperature

Years on Record: 48

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
C		-27.8		-27.8		-25.6		-18.3		-8.3		-2.2		2.2		5		3.3		-1.1		-9.4		-12.8		-20

Average Number of Days Above 90F/32C

Years on Record: 48

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		29.9		---		---		---		0.3		1		5.5		11.3		8.8		2.9		0.1		---		---

Average Number of Days Below 32F/0C

Years on Record: 48

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		111.1		25.4		22.4		16.4		5		0.4		---		---		---		---		4.3		13.8		23.4

Average Number of Days Below 0F/-17C

Years on Record: 48

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		1.4		1		0.3		---		---		---		---		---		---		---		---		---		0.1

Average Precipitation

Years on Record: 48

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
mm		1048		72		68		85		81		106		105		91		95		98		83		83		80

Average Number of Days With Precipitation

Years on Record: 48

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		117		10		9		10		10		12		11		11		9		9		8		9		10

Most Precipitation Reported in a Day

Years on Record: 48

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
mm.		271		45.5		59.2		56.1		73.7		94.7		271		88.9		118.9		140.2		103.1		65.8		74.2

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

Years on Record: 48

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		73		6		5		7		6		8		7		6		6		5		5		6		6

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

Years on Record: 48

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		28		2		2		2		2		3		3		2		2		3		2		2		2

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

Years on Record: 48

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		10		1		1		1		1		1		1		1		1		1		1		1		1

Most Rain Reported in a Month

Years on Record: 48

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
mm		1668		168		159		194		187		261		462		199		272		286		234		199		171

Least Rain Reported in a Month

Years on Record: 48

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
mm		686		10		6		2		8		9		13		24		11		4		---		6		11

Average Snowfall

Years on Record: 48

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
cm.		58.2		18		19.1		7.9		0.8		---		---		---		---		---		---		2		10.2

Most Snow Reported in a Month

Years on Record: 48

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
cm.		138.7		78.5		117.1		39.4		10.2		---		---		---		---		---		3.3		29		61.5

Heating Degree Days

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		2781.1		592.2		488.3		375.6		205		77.8		3.9		---		---		24.4		177.2		326.7		510

Cooling Degree Days

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		540.6		---		---		---		---		29.4		103.9		182.8		158.3		59.4		6.7		---		---

Growing Degree Days

Years on Record: 48

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		1893.2		---		---		---		60		217		358.3		447.8		427.1		291.7		91.3		---		---

Average Length of Day

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Hours		12.7		10.3		11.2		12.4		13.7		14.8		15.4		15.1		14.1		12.8		11.6		10.5		10

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		7.1		9.9		13.4		16.8		19.2		20.3		20.1		17.9		15.3		12.1		8		6.2

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		4		5.5		7.2		8.3		8.9		8.6		7.6		5.9		4.3		3.2		2.7

Average Daily Solar Radiation - Reflected

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		15.3		11.2		13.4		15.6		17		17.6		17.8		17.9		17.3		17		16.3		12.3		10.3

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		11.3		13.4		14.7		15.8		16.9		17.4		17.6		16.4		16.6		16.6		12.6		10.4

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		7.1		9.9		13.4		16.8		19.2		20.3		20.1		17.9		15.3		12.1		8		6.2

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		3		4.1		5.7		7.4		8.6		9.1		8.8		7.8		6.3		4.6		3.3		2.7

Maximum Daily Solar Radiation - Reflected

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		18.1		13.4		16.7		18.9		19.4		20.7		20.7		19.5		19.3		19.9		20.6		15.6		12.3

Maximum Daily Solar Radiation - Direct

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		19.6		14		18.5		19.8		20		23.1		23.6		20.8		20		21.5		23.1		17.4		13

Minimum Daily Solar Radiation - Global

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		11.4		6		7.9		10.8		14.5		12.7		17.1		17.9		15.8		13.1		9.8		5.9		4.8

Minimum Daily Solar Radiation - Diffuse

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		5.4		2.8		3.6		5.1		6.8		7.7		8.3		8.3		7.3		5.4		3.5		2.8		2.6

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		9		9.9		12.1		14.5		11.7		15.1		16.1		15.3		14.1		12.3		8.1		7.2

Minimum Daily Solar Radiation - Direct

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		10.1		8.3		8.6		9.7		11.8		7.2		12.1		13.9		12.9		12.2		10.8		7		6.4