PRESTON, MARYLAND

Average Temperature

Years on Record: 27

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
C		13.4		2		3		6.8		12.4		17.7		22.6		24.9		23.8		20.3		14.7		8.8		3.6

Average High Temperature

Years on Record: 27

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
C		19.2		6.9		8.2		12.4		18.8		24.1		28.8		30.8		29.8		26.5		20.9		14.4		8.4

Average Low Temperature

Years on Record: 27

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
C		7.6		-2.8		-2.2		1.1		6		11.3		16.5		18.9		17.9		14.1		8.5		3.1		-1.3

Highest Recorded Temperature

Years on Record: 27

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
C		38.9		24.4		23.9		26.7		33.3		35		37.8		38.9		37.8		36.1		34.4		28.9		22.2

Lowest Recorded Temperature

Years on Record: 27

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
C		-21.7		-21.7		-17.8		-16.7		-6.1		-0.6		5		8.9		7.2		0.6		-5.6		-8.3		-19.4

Average Number of Days Above 90F/32C

Years on Record: 27

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		27.9		---		---		---		0.3		1		6.4		10.6		7.1		2.4		0.1		---		---

Average Number of Days Below 32F/0C

Years on Record: 27

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		92		22.7		19.3		14.1		3.6		0.1		---		---		---		---		2		10.1		20.1

Average Number of Days Below 0F/-17C

Years on Record: 27

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		0.4		0.2		0.1		---		---		---		---		---		---		---		---		---		---

Average Precipitation

Years on Record: 27

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
mm		1052		76		74		91		78		84		87		92		135		90		78		81		86

Average Number of Days With Precipitation

Years on Record: 27

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		106		10		9		11		10		10		8		8		9		7		7		8		9

Most Precipitation Reported in a Day

Years on Record: 27

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
mm.		181.4		72.4		38.4		68.8		41.9		68.8		78.2		95.8		149.1		181.4		104.1		86.4		57.4

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

Years on Record: 27

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		70		6		6		7		7		6		6		5		6		5		5		5		6

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

Years on Record: 27

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

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

Years on Record: 27

		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

Most Rain Reported in a Month

Years on Record: 27

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
mm		1404		154		148		173		147		155		214		237		403		217		182		192		191

Least Rain Reported in a Month

Years on Record: 27

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
mm		806		16		21		42		22		10		16		24		18		27		---		9		16

Average Snowfall

Years on Record: 27

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
cm.		40.4		12.4		11.7		7.4		1		---		---		---		---		---		---		2.3		5.8

Most Snow Reported in a Month

Years on Record: 27

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
cm.		113		71.1		59.7		38.1		7.6		---		---		---		---		---		---		28.7		20.3

Heating Degree Days

Years on Record: 27

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		2718.3		505.5		433.2		358.2		177.5		20.7		---		---		---		---		111.9		286.7		458.1

Cooling Degree Days

Years on Record: 27

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		562.1		---		---		---		---		---		129.2		203.2		170.5		59.2		---		---		---

Growing Degree Days

Years on Record: 27

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		2035.4		---		---		---		72.5		237.7		379.2		461.6		428.8		309.2		146.4		---		---

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		11.3		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		14		7.2		10.1		13.4		16.9		19.1		20.6		19.9		18.2		15.6		12.1		8.2		6.4

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		7.5		5.9		4.3		3.2		2.6

Average Daily Solar Radiation - Reflected

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		15.5		11.5		13.6		15.7		17		17.5		18		17.8		17.7		17.2		16.3		12.6		10.9

Average Daily Solar Radiation - Direct

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		15.3		11.6		13.9		14.8		15.9		16.7		17.9		17.4		17.1		17.1		16.6		13		11.2

Maximum Daily Solar Radiation - Global

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		14		7.2		10.1		13.4		16.9		19.1		20.6		19.9		18.2		15.6		12.1		8.2		6.4

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		7.7		6.2		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		13.3		17.4		18.4		19.2		20.4		19.8		19.3		20.5		19.6		20.7		15.7		12.7

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		14.2		19.6		19		19.7		22.5		21.6		20.5		22.4		20.9		23.4		17.6		13.6

Minimum Daily Solar Radiation - Global

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		11.5		5.9		8		11.3		14.9		12.2		17.3		17.8		16.4		13.2		10		6.4		4.9

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		3.5		5.2		6.9		7.8		8.5		8.3		7		5.5		3.5		2.8		2.5

Minimum Daily Solar Radiation - Reflected

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		12.3		8.8		10		12.7		14.9		11.2		15.3		16		15.8		14.2		12.7		8.9		7.3

Minimum Daily Solar Radiation - Direct

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Mj/m2		10.4		8.1		8.7		10.4		12.5		6.5		12.5		13.8		13.8		12.3		11.4		8.1		6.5