Editing Sonora (section)

===Climate===
[[File:Sonoran desert sunset.jpg|thumb|Sunset over the desert in Sonora]]
During the [[Pliocene]], the detachment of Baja California, the development of the Gulf of California and the cool California current drastically reduced moisture coming into Sonora leading to severe regional aridity in both this state and neighboring Baja California. This created [[xeric]] communities and the development of species endemic only to this region.<ref name="cartron44">Cartron, p. 44</ref>

There are four major climate regions in the state: arid ([[Köppen climate classification|Köppen]] ''BW''), [[semi-arid climate|semi-arid]] lands (''BS''), semi-moist lands, and temperate zones (''Cwb'').<ref name="cartron19">Cartron, p. 19</ref> Ninety percent of the state has arid or semi-arid conditions. The other two climates are restricted to the areas of the state with the highest altitude such as the Yécora area, the mountains north of [[Cananea]] and a strip along the southeast of the state on the Chihuahua border.<ref name="mediofisico"/><ref name="gobiernosonora"/>

Average annual maximum temperatures range from {{convert|24.2|C|F}} in Yécora to {{convert|35|C|F}} in Tesia, municipality of [[Navojoa]]. Average annual minimum temperatures range from {{convert|5.9|C|F|1}} in Yécora to {{convert|20.2|C|F|1}} in Orégano, municipality of [[Hermosillo]].<ref name="mediofisico"/><ref name="gobiernosonora"/> In the winter, cold air masses from the north reach the state, and can produce below freezing temperatures and high winds at night in the higher elevations, but the temperature can then jump back up to over {{convert|20|C|F|disp=or}} during the afternoon. Freezing temperatures almost never occur in the lowlands.<ref name="yetman10"/><ref name="registra">{{cite news |title= Sonora registra 12 grados bajo cero |url= http://eleconomista.com.mx/estados/2011/02/05/sonora-registra-12-grados-bajo-cero |agency= Notimex |newspaper=El Economista |location=Mexico |date=February 5, 2011 |access-date=February 15, 2011 |language=es |trans-title=Sonora registes 12 degrees below zero}}</ref> In February 2011, the Mexican government recorded a low in Yécora of {{convert|&minus;12|C|F|1|disp=or}}.<ref name="registra"/>

[[File:San Carlos Sonora landscape.jpg|thumb|San Carlos during the wet season]]
Precipitation is seasonal and mostly occurs in the higher elevations. In hot and arid or semi-arid lands, evaporation vastly exceeds precipitation.<ref name="yetman9">Yetman, p. 9</ref> Mexico's most arid area, the [[Altar Desert]] is located in this state.<ref name="gobiernosonora"/> The east of the state is dominated by the Sierra Madre Occidental, which has less extreme temperatures and relatively more rainfall due to altitude.<ref name="gobiernosonora"/> Most moisture comes in from the Pacific Ocean and the tropics, which is pushed against the Sierra Madre. This cools the air masses, leading to rain and occasionally snow in the higher elevations. While most of the rain falls in the mountainous areas, much of this water finds its way back to the western coastal plains in the form of rivers and streams that empty into the Gulf of California and fill underground [[aquifer]]s.<ref name="yetman15"/> Most of the year's precipitation falls during the rainy season, which is locally called "las aguas" (the waters). These last from July to mid-September, when [[monsoon]] winds bring moist air from southerly tropical waters. Most of this is from the Pacific Ocean west of [[Central America]] but can also come from [[Gulf of Mexico]] as well. This moister flow results in nearly daily afternoon thunderstorms. After the las aguas, there may be additional moisture brought in by hurricanes, which generally move west along the Pacific coast of Mexico and occasionally come inland, especially in southern Sonora. However, these storms tend to drop large quantities of rain in a short time, causing flooding and destruction.<ref name="yetman11"/>

In the winter, from November to February, there are light rains called ''equipatas'' ("horse hoofs", named after the sound the rain makes). These rains come in from the north from the southern extensions of frontal storms that originate in the northern Pacific Ocean. These end by March or April when the fronts are no longer strong enough to reach this far south. They end even earlier in the extreme south of the state as the storm systems retreat, with the dry season lasting eight or nine months in this part of the state. In the north, these rains support a wide variety of spring annuals and wildflowers, but the water they supply in the south of the state is still important to help replenish wells.<ref name="yetman11"/>