ARLINGTON, VIRGINIA

Average Temperature

Years on Record: 51

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
C		14		2		3		7		13		18		23		26		25		21		15		9		3

Average High Temperature

Years on Record: 51

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
C		19		6		7		12		19		24		28		31		30		26		20		14		8

Average Low Temperature

Years on Record: 51

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
C		9		-2		-1		2		7		13		18		21		20		16		10		4		---

Highest Recorded Temperature

Years on Record: 51

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
C		40		26		27		31		35		37		38		40		39		38		34		30		23

Lowest Recorded Temperature

Years on Record: 51

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
C		-20		-20		-15		-10		-4		1		8		12		9		3		-1		-8		-16

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
mm		990		70		60		80		70		90		80		100		100		80		70		70		70

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
mm		1460		180		140		210		170		270		290		320		360		310		210		170		160

Least Recorded Rainfall

Years on Record: 51

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
mm		680		---		10		10		---		20		20		20		10		---		---		---		---

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
C		7		-5		-4		---		4		11		16		18		18		15		8		2		-2

Heating Degree Days

Years on Record: 51

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		2552.7		508.1		423.8		327.2		141.7		---		---		---		---		---		94.7		266.7		439.2

Cooling Degree Days

Years on Record: 51

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		731.9		---		---		---		---		17.2		158.3		241.1		215.3		100		---		---		---

Growing Degree Days

Years on Record: 51

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		2278.8		---		---		---		108.3		275.6		408.3		499.4		473.6		350		163.6		---		---

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
km/h		16		20		20		20		14		14		14		14		14		14		14		14		20

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