Drought, which began the year mostly confined to the southern United States, charged northward and intensified during the spring and summer, eventually becoming the Nation's worst agricultural calamity since 1988. Complicating and exacerbating the drought situation, the Nation suffered through its hottest year on record, fueled by record-warmth during the spring and the third-hottest summer.
As result, nearly two-thirds (63.86 percent) of the contiguous United States was in drought, according to the United States Drought Monitor, by late July. Drought coverage eventually peaked on September 25, with 65.45 percent of the country affected.
According to preliminary data provided by the National Climatic Data Center, the Nation's annual average temperature of 55.3 degrees Fahrenheit was 3.3 degrees above the 1901-2000 mean, demolishing the 1998 standard of 54.3 degrees Fahrenheit. In fact, seven of the Nation's ten warmest years on record have occurred in the last 15 years (along with 1998 and 2012, they are 1999, 2001, 2005, 2006, and 2007).
The only pre-1998 years still on the record books for top-ten warmth are 1921, 1931, and 1934. During 2012, all but three (Georgia, Oregon, and Washington) of the Lower 48 States reported one of their ten warmest years on record, and 19 States from the Southwest to the Northeast set annual records for warmth.
The Nation also suffered through its driest year since 1988, and fifteenth-driest year on record. Annual precipitation averaged 26.57 inches (91 percent of normal) across the contiguous United States. For Nebraska and Wyoming, it was the hottest, driest year on record; Nebraska's record for dryness had stood since 1934.
Near-record dryness dominated several other States, including Arkansas, Colorado, Delaware, Georgia, Illinois, Kansas, Missouri, and New Mexico. In contrast, relatively wet conditions prevailed during 2012 in the Pacific Northwest, the central Gulf Coast region, and parts of the Northeast. Washington ranked highest, reporting its fifth-wettest year.
Winter 2011-12: The winter of 2011-12 featured little in the way of sustained cold, especially east of the Rockies. However, even in a winter without much cold weather, Florida's peninsula endured a brief freeze on January 4-5, as well as several other minor cool snaps. Farther north, winter wheat largely escaped without significant cold-season damage despite a general lack of snow cover and occasional high winds. Nevertheless, the southern High Plains wheat crop, not to mention rangeland and pastures, continued to suffer from aftereffects of the historic drought of 2011. Meanwhile, precipitation was considerably below normal across much of the western United States, except for unusually heavy December rain and snow in the Southwest and periods of mid- to late-winter storminess in the Northwest. Drier than normal conditions also plagued parts of the Atlantic Coast States, leading to worsening drought across the lower Southeast. Notable winter wetness was generally confined to the Nation's mid-section, stretching from portions of the central and southern Plains into the Ohio Valley.
Spring: Unprecedented spring warmth covered much of the central and eastern United States, promoting rapid crop planting and development but reducing soil moisture reserves due to above average evaporation rates and crop demands. In much of the West, unusual warmth caused premature melting of high-elevation snow packs. Both March and spring (March-May) United States temperatures surpassed records originally set more than a century ago, in 1910. Warmth left fruits vulnerable to spring cold snaps, and a series of freezes (from late March to late April) in the lower Great Lakes region and the Northeast damaged a variety of crops. Meanwhile, consistently cool conditions were confined to the Pacific Northwest. In the Sierra Nevada, significant spring precipitation turned a dismal wet season into merely a poor one. Farther inland, the wet season ended on a dry note, especially in Colorado, Utah, and Wyoming.
However, all of those States - as well as California and Nevada - had a buffer against developing drought in the form of abundant reservoir storage. Elsewhere in the West, heavy precipitation from the Pacific Northwest to the northern Rockies contrasted with drier than normal conditions (and below average reservoir storage) in Arizona and New Mexico. Farther east, late-spring rainfall eased dry conditions across the northern Plains and upper Midwest, but developing drought remained a concern in the central Plains, southern and eastern Corn Belt, and Mid-South. During May, Tropical Storm Beryl contributed to a favorably wetter pattern in the East.
Summer: The Nation's worst agricultural drought since 1988 harmed corn, soybeans, sorghum, pastures and rangeland, as well as a variety of other commodities. Corn and soybean conditions, as reported by USDA/NASS, were comparable to those observed during the 1988 drought, while pasture conditions (reported only since 1995) reached a record-high 59 percent very poor to poor during 5 consecutive weeks in August and early September. In contrast, mid- to late-summer rainfall revived pastures and aided immature summer crops across the South, East, and lower Midwest. By summer's end, at least half of the pastures were rated good to excellent in every coastal State from Louisiana to Maryland. Rainfall became excessive, however, in late August, when Hurricane Isaac rolled into Louisiana. Isaac battered the central Gulf Coast with wind, torrential rainfall, and a coastal storm surge. The storm's remnants eventually provided drought relief to parts of the Mid-South and lower Midwest.
Autumn: Dry conditions strengthened their grip on the Nation's mid-section, maintaining severe stress on rangeland and pastures and resulting in poor establishment of the Plains' hard red winter wheat crop. On the southern Plains, extremely dry conditions prevailed in October and November following a promising start to the winter wheat growing season in September. In contrast, relatively wet conditions developed in October and November across northern California, the Northwest, and portions of the northern Plains, helping to offset an exceedingly dry September. Unfortunately, most of the precipitation failed to reach the Southwest, where drought remained deeply entrenched.
Farther east, autumn rainfall largely eradicated drought from the eastern Corn Belt, but soil moisture shortages remained a serious concern across the western Corn Belt. At the end of October, the remnants of Hurricane Sandy contributed to an overall wet pattern across the lower Great Lakes region. Sandy's most profound impacts were felt across the northern Mid-Atlantic region, battered by high winds and a record-setting storm surge, and the central and southern Appalachians, blanketed by heavy snow.