RESTON, VIRGINIA

Average Temperature

Years on Record: 48

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
F		54.4		32.1		34.5		43.7		53.6		62.6		71.5		76		74.8		67.5		55.3		45.8		35.9

Average High Temperature

Years on Record: 48

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
F		65.5		41.4		44.6		54.9		66		74.6		83		87.2		86		79		67.6		56.8		45.3

Average Low Temperature

Years on Record: 48

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
F		43.4		22.8		24.3		32.4		41.3		50.7		60		64.9		63.6		56		43.1		34.7		26.5

Highest Recorded Temperature

Years on Record: 48

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
F		104		75		79		89		93		97		100		104		104		99		94		84		79

Lowest Recorded Temperature

Years on Record: 48

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
F		-18		-18		-14		-1		17		28		36		41		38		30		15		9		-4

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
in.		41.3		2.8		2.7		3.4		3.2		4.2		4.2		3.6		3.7		3.8		3.2		3.3		3.2

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
in.		10.7		1.8		2.3		2.2		2.9		3.7		10.7		3.5		4.7		5.5		4.1		2.6		2.9

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
in.		65.7		6.6		6.3		7.7		7.3		10.3		18.2		7.8		10.7		11.3		9.2		7.8		6.7

Least Rain Reported in a Month

Years on Record: 48

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
in.		27		0.4		0.2		0.1		0.3		0.3		0.5		0.9		0.4		0.2		---		0.2		0.4

Average Snowfall

Years on Record: 48

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
in.		22.9		7.1		7.5		3.1		0.3		---		---		---		---		---		---		0.8		4

Most Snow Reported in a Month

Years on Record: 48

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
in.		54.6		30.9		46.1		15.5		4		---		---		---		---		---		1.3		11.4		24.2

Heating Degree Days

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		5006		1066		879		676		369		140		7		---		---		44		319		588		918

Cooling Degree Days

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		973		---		---		---		---		53		187		329		285		107		12		---		---

Growing Degree Days

Years on Record: 48

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		3407.7		---		---		---		108		390.6		645		806		768.8		525		164.3		---		---

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
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