Find the city closest to you and select the low value for your calculation (the worst case value) for off-grid systems.

State	City	High	Low	Avg		State	City	High	Low	Avg
AK	Fairbanks	5.87	2.12	3.99		MO	Columbia	5.50	3.97	4.73
AK	Matanuska	5.24	1.74	3.55		MO	St. Louis	4.87	3.24	4.38
AL	Montgomery	4.69	3.37	4.23		MS	Meridian	4.86	3.64	4.43
AR	Bethel	6.29	2.37	3.81		MT	Glasgow	5.97	4.09	5.15
AR	Little Rock	5.29	3.88	4.69		MT	Great Falls	5.70	3.66	4.93
AZ	Tucson	7.42	6.01	6.57		MT	Summit	5.17	2.36	3.99
AZ	Page	7.30	5.65	6.36		NM	Albuquerque	7.16	6.21	6.77
AZ	Phoenix	7.13	5.78	6.58		NB	Lincoln	5.40	4.38	4.79
CA	Santa Maria	6.52	5.42	5.94		NB	N. Omaha	5.28	4.26	4.90
CA	Riverside	6.35	5.35	5.87		NC	Cape Hatteras	5.81	4.69	5.31
CA	Davis	6.09	3.31	5.10		NC	Greensboro	5.05	4.00	4.71
CA	Fresno	6.19	3.42	5.38		ND	Bismarck	5.48	3.97	5.01
CA	Los Angeles	6.14	5.03	5.62		NJ	Sea Brook	4.76	3.20	4.21
CA	Soda Springs	6.47	4.40	5.60		NV	Las Vegas	7.13	5.84	6.41
CA	La Jolla	5.24	4.29	4.77		NV	Ely	6.48	5.49	5.98
CA	Inyokern	8.70	6.87	7.66		NY	Binghamton	3.93	1.62	3.16
CO	Grandby	7.47	5.15	5.69		NY	Ithaca	4.57	2.29	3.79
CO	Grand Lake	5.86	3.56	5.08		NY	Schenectady	3.92	2.53	3.55
CO	Grand Junction	6.34	5.23	5.85		NY	Rochester	4.22	1.58	3.31
CO	Boulder	5.72	4.44	4.87		NY	New York City	4.97	3.03	4.08
DC	Washington	4.69	3.37	4.23		OH	Columbus	5.26	2.66	4.15
FL	Appalachicola	5.98	4.92	5.49		OH	Cleveland	4.79	2.69	3.94
FL	Belie Is.	5.31	4.58	4.99		OK	Stillwater	5.52	4.22	4.99
FL	Miami	6.26	5.05	5.62		OK	Oklahoma City	6.26	4.98	5.59
FL	Gainesville	5.81	4.71	5.27		OR	Astoria	4.76	1.99	3.72
FL	Tampa	6.16	5.26	5.67		OR	Corvallis	5.71	1.90	4.03
GA	Atlanta	5.16	4.09	4.74		OR	Medford	5.84	2.02	4.51
GA	Griffin	5.41	4.26	4.99		PA	Pittsburgh	4.19	1.45	3.28
HI	Honolulu	6.71	5.59	6.02		PA	State College	4.44	2.79	3.91
IA	Ames	4.80	3.73	4.40		RI	Newport	4.69	3.58	4.23
ID	Boise	5.83	3.33	4.92		SC	Charleston	5.72	4.23	5.06
ID	Twin Falls	5.42	3.42	4.70		SD	Rapid City	5.91	4.56	5.23
IL	Chicago	4.08	1.47	3.14		TN	Nashville	5.20	3.14	4.45
IN	Indianapolis	5.02	2.55	4.21		TN	Oak Ridge	5.06	3.22	4.37
KN	Manhattan	5.08	3.62	4.57		TX	San Antonio	5.88	4.65	5.30
KN	Dodge City	4.14	5.28	5.79		TX	Brownsville	5.49	4.42	4.92
KY	Lexington	5.97	3.60	4.94		TX	El Paso	7.42	5.87	6.72
LA	Lake Charles	5.73	4.29	4.93		TX	Midland	6.33	5.23	5.83
LA	New Orleans	5.71	3.63	4.92		TX	Fort Worth	6.00	4.80	5.43
LA	Shreveport	4.99	3.87	4.63		UT	Salt Lake City	6.09	3.78	5.26
MA	E. Wareham	4.48	3.06	3.99		UT	Flaming Gorge	6.63	5.48	5.83
MA	Boston	4.27	2.99	3.84		VA	Richmond	4.50	3.37	4.13
MA	Blue Hill	4.38	3.33	4.05		WA	Seattle	4.83	1.60	3.57
MA	Natick	4.62	3.09	4.10		WA	Richland	6.13	2.01	4.44
MA	Lynn	4.60	2.33	3.79		WA	Pullman	6.07	2.90	4.73
MD	Silver Hill	4.71	3.84	4.47		WA	Spokane	5.53	1.16	4.48
ME	Caribou	5.62	2.57	4.19		WA	Prosser	6.21	3.06	5.03
ME	Portland	5.23	3.56	4.51		WI	Madison	4.85	3.28	4.29
MI	Saulte Ste. Marie	4.83	2.33	4.20		WV	Charleston	4.12	2.47	3.65
MI	E. Lansing	4.71	2.70	4.00		WY	Lander	6.81	5.50	6.06
MN	St. Cloud	5.43	3.53	4.53

Source: National Renewable Energy Laboratory