Annual Rainfall for U.S. States

I was playing a trivia game and the question was "Which U.S. state gets the least annual rainfall?" My answer was "Rhode Island," which most people think is pretty funny. (O.K., so the question should have said "the least annual rainfall per unit area," but it didn't.)

So I decided to try to find out which U.S. state really does get the least total annual rainfall. I found the area of each state in square miles and the average annual rainfall, in inches, for selected cities in each state. To get the units consistent, I convert the rainfall from inches to miles. Then I multiply the area by the rainfall to get the cubic miles of annual rainfall for the state.

Admittedly, this is not perfect. For example, the only rainfall figure I have for Alaska is for Juneau, which is much wetter than the rest of the state. (In fact, I think Alaska was the answer the game had for the state with the least annual rainfall. Much of the state is very dry.) Still, I think the figures make a pretty good case for Rhode Island getting the least rainfall. Judge for yourself.

State	Area (sq. mi.)	Rainfall (in./yr.)^*	Rainfall (mi./yr.)	Rainfall (cu. mi./yr.)
Alabama	51,609	56.90	0.0008980	46.3471
Alaska	586,412	53.15	0.0008389	491.9160
Arizona	113,909	7.11	0.0001122	12.7824
Arkansas	53,104	49.20	0.0007765	41.2361
California	158,693	17.28	0.0002727	43.2799
Colorado	104,247	15.31	0.0002416	25.1897
Connecticut	5,009	44.39	0.0007006	3.5093
Delaware	2,057	41.38	0.0006531	1.3434
Florida	58,560	49.91	0.0007877	46.1289
Georgia	58,876	48.61	0.0007672	45.1699
Hawaii	6,450	23.47	0.0003704	2.3892
Idaho	83,557	11.71	0.0001848	15.4427
Illinois	56,400	33.34	0.0005262	29.6777
Indiana	36,291	39.12	0.0006174	22.4069
Iowa	56,290	34.71	0.0005478	30.8369
Kansas	82,264	28.61	0.0004515	37.1460
Kentucky	40,409	43.56	0.0006875	27.7812
Louisiana	48,523	59.74	0.0009429	45.7507
Maine	33,215	43.52	0.0006869	22.8143
Maryland	10,577	41.84	0.0006604	6.9846
Massachusetts	8,257	43.84	0.0006919	5.7132
Michigan	58,216	32.23	0.0005086	29.6088
Minnesota	84,068	26.36	0.0004160	34.9753
Mississippi	47,716	52.82	0.0008336	39.7784
Missouri	69,686	33.91	0.0005352	37.2956
Montana	147,138	11.37	0.0001795	26.4040
Nebraska	77,227	30.34	0.0004789	36.9802
Nevada	110,540	7.87	0.0001242	13.7303
New Hampshire	9,304	36.53	0.0005765	5.3642
New Jersey	7,836	41.93	0.0006618	5.1859
New Mexico	121,666	8.91	0.0001406	17.1062
New York	49,576	39.28	0.0006199	30.7322
North Carolina	52,586	42.46	0.0006701	35.2399
North Dakota	70,665	15.36	0.0002424	17.1309
Ohio	41,222	37.77	0.0005961	24.5732
Oklahoma	69,919	30.89	0.0004875	34.0877
Oregon	96,981	37.39	0.0005901	57.2304
Pennsylvania	45,333	40.26	0.0006353	28.8018
Rhode Island	1,214	41.91	0.0006615	0.8030
South Carolina	31,055	51.59	0.0008142	25.2861
South Dakota	77,047	17.47	0.0002756	21.2378
Tennessee	42,244	48.49	0.0007653	32.3297
Texas	267,338	34.70	0.0005477	146.4114
Utah	84,916	15.31	0.0002416	20.5187
Vermont	9,609	33.69	0.0005317	5.1093
Virginia	40,817	45.22	0.0007137	29.1311
Washington	68,192	27.66	0.0004365	29.7640
West Virginia	24,181	40.74	0.0006430	15.5482
Wisconsin	56,154	30.89	0.0004875	27.3768
Wyoming	97,914	13.31	0.0002101	20.5687

Source: The World Almanac 1988

^*Based on rainfall for selected cities. Where values are available for more than one city in a state, the average of those values is used.

This table is also available in Excel format.

HowStuffWorks has a cool map of annual rainfall amounts throughout the United States.

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