The semitropics and subtropics refer to regions of the Earth immediately north and south of the two tropic regions, which are bounded by the Tropic of Cancer and the Tropic of Capricorn, at latitude 23.5 ° north and south. The subtropics are therefore the next higher latitudinal regions above the tropics. The Tropic of Cancer passes through the following countries (going east): Hawaii, Mexico, Bahamas, Western Sahara, Mali, Libya, Egypt, Saudi Arabia, United Arab Emirates, India, Bangladesh, China,  Taiwan and other. The line is called the Tropic of Cancer because when it was named, the sun was in the constellation of Cancer when it appeared directly overhead at this latitude during the June solstice.

 The term semitropical can be used to mean a range of latitudes between 23.5 and approximately 35 degrees. A semitropical climate implies that the air temperature usually does not go below freezing (0°C). This is a threshold temperature for a gamut of plants, and applies to coastal California, southern Florida, coastal Australia, and coastal South Africa, for example. The pole ward limit of subtropical climates is higher on the west coasts of the northern continents and lower on the east coasts, because occasional winter cold snaps reach farther south in the east.

 Hawaii is the most recently admitted state of the United States. In addition, to possessing the southernmost point in the United States it is the only state that lies completely in the tropics. The climate of Hawaii is atypical for a tropical area and regarded as more semitropical than the latitude would suggest because of the moderating effect of the surrounding ocean. Temperatures and humidity tend to be less extreme, with summer high temperatures seldom reaching above the upper 80's (°F) and winter temperatures (at low elevation) seldom dipping below the mid-60's. Snow, although not usually associated with tropics, falls at high elevations on Mauna Kea and Mauna Loa on the Big Island in some winter months. Snow only rarely falls on Maui's Haleakala. Local subtropical climates vary considerably on each island.

 While Florida's nickname is the "Sunshine State", severe weather is a common occurrence in Florida. Central Florida is known as the Lightning capital of the U.S. as it experiences more lightning strikes than anywhere else in the country. The semitropical climate of Florida is tempered somewhat by its proximity to water. Most of the state has a humid semitropical climate with the extreme tip of Florida and the Florida Keys bordering on a true tropical climate. Cold fronts can occasionally bring high winds and cool to cold temperatures to the entire state during late fall and winter. One such front swept through the peninsula on November 25, 1996 bringing cold temperatures and winds up to 95 mph, knocking out power to thousands, and damaging mobile homes.

However, Florida averages 300 days of full sunshine a year. The seasons in Florida often called "Hot and Hotter" are actually determined more by precipitation than by temperature with warm, relatively dry winters and autumns (the dry season) and hot, wet springs and especially the summers (the wet season). The Gulf Stream has a moderating effect on Florida semitropical climate and although it is common for much of Florida to see a high summer temperature over 90 degrees Fahrenheit (32 °C), it is not common for the mercury to go above 100 degrees Fahrenheit (39 °C) in Florida.