image of the Cincinnati metropolitan area. The
Ohio River separates the states of Ohio and Kentucky. The Cincinnati–Northern Kentucky metropolitan area is located within a climatic transition zone. The southern area of the region, from roughly about the Ohio River, is at the extreme northern limit of the
humid subtropical climate; the north part of the region is on the extreme southern cusp of the
humid continental climate. Evidence of both humid subtropical climate and humid continental climate can be found here, particularly noticeable by the presence of plants indicative of each climatic region. Within the area, the
USDA climate zone rating can vary from as warm as zone 6b to as cool as zone 5b, with the warmest areas tending to be found closest to the
Ohio River; individual
microclimates of even cooler and warmer temperature may occur in the area but are too small to be considered in the overall climate zone rating. The
common wall lizard, introduced from Italy in the 1950s, is an example of fauna in the area that lends a subtropical ambiance to the urban core (near downtown Cincinnati) area of the region. Significant moderating variables for the overall climate are: • South and central: Ohio River,
Licking River, relatively large hills and valleys, and a combined
urban heat island effect due to the close proximity of the Cincinnati-Northern Kentucky cities of Covington, Newport, and Downtown Cincinnati • Suburban: large parking lots that take up much land in Mason, West Chester, and Florence create a heat island effect. • North:
Great Miami River, the area is situated on a glaciated flat plateau, the Miami Valley, and some urban heat island effect in the immediate area of downtown Dayton and Hamilton. Traveling through the region from North to South, a subtle but interesting change in climate can be observed and is most evidenced by the gradual increase in the occurrence of subtropical indicator plants in the landscape. Most noticeable are the Southern Magnolia and
Mimosa trees, and the
needle palm also may be found as a winter hardy landscape specimen in lawns near the Ohio River. During the winter, travellers from north to south will routinely observe a significant difference in snowfall/ice/rain in the region. Although widely accepted as part of the very southern fringe of the
Midwestern United States in most cases, the Cincinnati–Northern Kentucky metropolitan area is climatically and geographically located on the northern periphery of the
Upland South region of the United States and is within the
Bluegrass region of Ohio and Kentucky in the Upper South. The area is vulnerable to occasional
severe weather—thunderstorms, large hail and sometimes tornadoes. ==Transportation==