ARLINGTON, VIRGINIA

Average Temperature

Years on Record: 51

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
F		58		36		38		46		57		66		75		79		78		71		60		49		39

Average High Temperature

Years on Record: 51

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
F		67		43		46		55		67		76		84		88		86		80		69		58		47

Average Low Temperature

Years on Record: 51

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
F		49		28		30		37		46		56		65		70		69		62		50		40		32

Highest Recorded Temperature

Years on Record: 51

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
F		104		79		82		89		95		99		101		104		103		101		94		86		75

Lowest Recorded Temperature

Years on Record: 51

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
F		-5		-5		4		14		24		34		47		54		49		39		29		16		3

Average Number of Days Above 90F/32C

Years on Record: 51

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		35		---		---		---		---		2		7		13		9		3		---		---		---

Average Number of Days Above 70F/21C

Years on Record: 51

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		177		---		1		4		11		24		29		31		31		27		15		4		1

Average Number of Days Below 32F/0C

Years on Record: 51

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		71		21		18		9		1		---		---		---		---		---		---		5		16

Average Number of Days Below 10F/-12C

Years on Record: 51

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

Average Precipitation

Years on Record: 51

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
in.		39.3		2.8		2.6		3.4		2.8		3.9		3.3		4		4.1		3.3		3		3		3.1

Average Number of Days With Thunderstorms

Years on Record: 50

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		31		---		---		1		3		5		6		7		5		2		1		1		---

Most Rain Reported in a Month

Years on Record: 51

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
in.		57.5		7.1		5.7		8.4		6.9		10.7		11.5		12.9		14.3		12.4		8.6		6.7		6.5

Least Recorded Rainfall

Years on Record: 51

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
in.		26.9		0.3		0.4		0.7		---		0.8		0.9		0.9		0.5		0.2		---		0.3		0.2

Average Morning Relative Humidity

Years on Record: 54

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
%		75		71		70		70		70		75		76		77		81		82		81		76		72

Average Evening Relative Humidity

Years on Record: 54

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
%		52		55		50		47		46		51		52		53		54		55		53		53		55

Average Dew Point

Years on Record: 54

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
F		45		23		24		31		40		52		61		66		65		59		48		37		27

Heating Degree Days

Years on Record: 51

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		3962.3		914.5		762.8		589		255		---		---		---		---		---		170.5		480		790.5

Cooling Degree Days

Years on Record: 51

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		1317.5		---		---		---		---		31		285		434		387.5		180		---		---		---

Growing Degree Days

Years on Record: 51

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		4102		---		---		---		195		496		735		899		852.5		630		294.5		---		---

Average Length of Day

Years on Record: 30

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

Average Number of Days With Fog

Years on Record: 50

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		130		11		10		10		9		12		10		10		11		12		13		11		11

Average Wind Speed

Years on Record: 54

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
mph		10		13		13		13		9		9		9		9		9		9		9		9		13

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		2		2.8		3.7		4.7		5.3		5.6		5.6		5		4.3		3.4		2.2		1.7

Average Daily Solar Radiation - Diffuse

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
kWh/m2		1.6		0.8		1.1		1.5		2		2.3		2.5		2.4		2.1		1.7		1.2		0.9		0.7

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		3.1		3.7		4.3		4.7		4.9		4.9		5		4.8		4.7		4.5		3.4		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		4.2		3.1		3.7		4.1		4.4		4.7		4.8		4.9		4.6		4.6		4.6		3.5		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		2		2.8		3.7		4.7		5.3		5.6		5.6		5		4.3		3.4		2.2		1.7

Maximum Daily Solar Radiation - Diffuse

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
kWh/m2		1.7		0.8		1.2		1.6		2.1		2.4		2.5		2.5		2.2		1.7		1.3		0.9		0.8

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		3.7		4.6		5.3		5.4		5.8		5.7		5.4		5.4		5.5		5.7		4.3		3.4

Maximum Daily Solar Radiation - Direct

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
kWh/m2		5.4		3.9		5.2		5.5		5.6		6.4		6.6		5.8		5.6		6		6.4		4.8		3.6

Minimum Daily Solar Radiation - Global

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
kWh/m2		3.2		1.7		2.2		3		4		3.5		4.7		5		4.4		3.7		2.7		1.6		1.3

Minimum Daily Solar Radiation - Diffuse

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
kWh/m2		1.5		0.8		1		1.4		1.9		2.2		2.3		2.3		2		1.5		1		0.8		0.7

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		2.5		2.8		3.4		4		3.3		4.2		4.5		4.2		3.9		3.4		2.2		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		2.8		2.3		2.4		2.7		3.3		2		3.4		3.9		3.6		3.4		3		1.9		1.8