ATTU ISLAND, ALASKA

Average Temperature

Years on Record: 45

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
F		38.8		30.3		30.2		---		34.8		38.9		43.9		48.3		50.5		47.8		42.1		35.5		31.9

Average High Temperature

Years on Record: 45

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
F		43		34.4		34		---		38.5		42.7		48.4		52.6		55.1		52.2		46.8		40		35.7

Average Low Temperature

Years on Record: 45

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
F		34.6		26.3		26.4		---		31		35.1		39.4		44.2		45.8		43.3		37.4		31		28.1

Highest Recorded Temperature

Years on Record: 45

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
F		90		49		51		90		59		64		72		70		68		61		54		49		90

Lowest Recorded Temperature

Years on Record: 45

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
F		-15		5		7		10		15		19		24		28		20		21		-15		2		-15

Average Number of Days Below 32F/0C

Years on Record: 45

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		157		31		26		25.1		19.6		5.7		1.2		0.1		0.6		1.2		4.6		18.1		24.2

Average Number of Days Below 0F/-17C

Years on Record: 45

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

Average Precipitation

Years on Record: 45

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
in.		52.6		3.8		3.6		3.3		3.8		2.9		2.9		4.2		6		6.3		6.6		4.6		4.6

Average Number of Days With Precipitation

Years on Record: 45

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		197		19		17		18		16		13		11		13		15		17		19		20		19

Most Reported Precipitation in a Month

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
in		21.2		9.3		7.4		6.8		8		6		7.5		10.3		21.2		15.5		11.5		9.3		10.1

Least Reported Precipitation in a Month

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
in		---		0.5		0.4		0.8		1		---		0.1		1.3		1		0.1		0.6		0.3		0.7

Most Precipitation Reported in a Day

Years on Record: 45

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
in		10		2.5		3.6		2.7		3.5		2.3		4.5		9		10		4.6		4.3		4		3.4

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

Years on Record: 45

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		114		11		10		9		9		7		5		8		10		11		12		11		11

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

Years on Record: 45

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		30		2		2		1		2		2		2		2		4		4		4		3		2

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

Years on Record: 45

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		13		1		1		---		1		---		1		1		2		2		2		1		1

Average Snowfall

Years on Record: 45

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
in		76.4		16.2		16.9		15		6.5		1.1		---		---		---		---		0.6		7.1		13

Average Snow Cover

Years on Record: 45

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
in.		3		7		10		10		5		---		---		---		---		---		---		1		2

Most Snow Reported in a Month

Years on Record: 45

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
in		42.9		35.5		34.7		42.9		35.1		16.3		---		---		---		---		9.2		25.1		33.6

Heating Degree Days

Years on Record: 45

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		5913		764		703		729		608		499		334		209		146		219		399		586		717

Growing Degree Days

Years on Record: 45

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Days		15.5		---		---		---		---		---		---		15.5		---		---		---		---		---

Average Length of Day

Years on Record: 30

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
Hours		12.9		8.9		10.5		12.5		14.6		16.6		17.6		17.1		15.3		13.2		11.2		9.4		8.4

Average Daily Solar Radiation - Global

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
kWh/m2		2.5		0.8		1.4		2.5		3.7		4.4		4.2		4		3.4		2.7		1.8		0.9		0.6

Average Daily Solar Radiation - Diffuse

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
kWh/m2		1.5		0.5		0.9		1.5		2.1		2.5		2.7		2.5		2.1		1.6		1		0.6		0.4

Average Daily Solar Radiation - Reflected

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
kWh/m2		2.8		1.4		2.2		3.1		3.8		4		3.6		3.5		3.2		3.1		2.6		1.5		1.1

Average Daily Solar Radiation - Direct

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
kWh/m2		2.3		1.2		1.9		2.6		3.2		3.4		2.7		2.5		2.3		2.7		2.3		1.3		1

Maximum Daily Solar Radiation - Global

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
kWh/m2		2.5		0.8		1.4		2.5		3.7		4.4		4.2		4		3.4		2.7		1.8		0.9		0.6

Maximum Daily Solar Radiation - Diffuse

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
kWh/m2		1.6		0.6		1		1.5		2.1		2.6		2.8		2.7		2.3		1.6		1.1		0.6		0.4

Maximum Daily Solar Radiation - Reflected

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
kWh/m2		3.3		1.8		2.6		3.6		4.5		4.7		4.4		4.1		4		3.9		3.1		1.7		1.4

Maximum Daily Solar Radiation - Direct

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
kWh/m2		3		1.6		2.4		3.1		4.3		4.6		4		3.5		3.4		3.6		2.9		1.6		1.2

Minimum Daily Solar Radiation - Global

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
kWh/m2		2.1		0.6		1.2		2.3		2.9		3.7		3.5		3.4		2.6		2.2		1.6		0.8		0.5

Minimum Daily Solar Radiation - Diffuse

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
kWh/m2		1.4		0.4		0.8		1.4		1.9		2.4		2.4		2.4		1.9		1.4		0.9		0.5		0.4

Minimum Daily Solar Radiation - Reflected

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
kWh/m2		2.2		1		1.8		2.8		2.8		3.4		3		3		2.4		2.4		2.2		1.2		0.9

Minimum Daily Solar Radiation - Direct

Years on Record: 22

		ANNUAL		JAN		FEB		MAR		APR		MAY		JUN		JUL		AUG		SEP		OCT		NOV		DEC
kWh/m2		1.6		0.8		1.5		2.2		1.9		2.3		1.8		1.8		1.4		1.7		1.9		1		0.7