Climate/Geography
CURRENT TEMPERATURES
Heart of the Coachella Valley
Situated in the geographic center of the Coachella Valley, Rancho Mirage's location has played a major role in its development and success. Because it lies among the coves and alluvial fans of the Santa Rosa Mountains, Rancho Mirage proved to be an ideal getaway destination within easy driving distance from the Los Angeles area. The development of 18 hole golf courses with country club living and its proximity to Palm Springs helped Rancho Mirage blossom into the high-quality resort city it is today.
Rancho Mirage's close proximity to the San Jacinto, Santa Rosa and San Gorgonio mountains and three award-winning resort hotels ensure that the City will continue to be a prime destination for both business and vacation travelers.
Rancho Mirage is geographically in the Colorado Desert, protected from most prevailing weather systems off of the Pacific Ocean by Mt. San Gorgonio (the highest peak in Southern California) and Mt. San Jacinto (the second highest). Average annual rainfall in Rancho Mirage is just 3.38 inches. The sun usually shines 350 of the year's 365 days.
Many year-round residents and seasonal residents are refugees from colder areas of North America who have escaped the snow and freezing temperatures.
No discussion of the geography of the Coachella Valley would be complete without mentioning that the valley, like all of California, lies in a seismically active area. There are earthquakes from time to time in area; however, none in modern history have done significant damage in Rancho Mirage. The San Andreas Fault runs through the Coachella Valley, parallel to Interstate 10 north of the freeway. The Coachella Valley is fairly stable on its bedrock foundation and doesn't experience the liquefaction of soil that is a common occurrence in Los Angeles area quakes. That said, it is still recommended that every resident be prepared with an earthquake survival kit and have a plan of action for his family just in case. The City of Rancho Mirage is well prepared for emergencies; there is an Emergency Services Commission and department head and an Emergency Operations Center already in place.
Average Daily Minimum - Maximum Temperatures in Rancho Mirage
| January | 41 - 69º F | July | 74 - 108º F |
| February | 45 - 74º F | August | 73 - 107º F |
| March | 48 - 79º F | September | 67 - 102º F |
| April | 54 - 87º F | October | 59 - 92º F |
| May | 60 -94º F | November | 48 - 79º F |
| June | 66 - 102º F | December | 42 - 70º F |
Relative Humidity Levels
| Month | 4 AM | Noon | 4 PM |
| January | 57% | 32% | 32% |
| April | 45% | 22% | 19% |
| July | 20% | 12% | 9% |
| October | 35% | 27% | 22% |
| Year Avg. | 39% | 23% | 20% |
Why We Have Winds
As they enter the Coachella Valley on Highway 111 and Interstate 10, westbound drivers coming out of the San Gorgonio Pass will notice the proliferation of windmills. Hundreds of energy-producing windmills stand beacon like a giant Christo art project. The Pass (created by the proximity of Mt. San Jacinto and Mt. San Gorgonio) and the desert itself are responsible for the wind belt that stretches through the valley along Interstate 10.
A scientific principle called the Venturi effect illustrates the wind phenomenon best. As the sun's rays heat up the desert floor, warm air rises and lessens the valley's air pressure. The lower air pressure of the Coachella Valley draws in the higher-pressure air masses from the coast. This inland airflow speeds up as it squeezes through the narrow San Gorgonio Pass, causing the stronger winds.
As the temperature increases in the summer, the warmer air rises more quickly and decreases the air pressure faster. The wind is partially a result of the differential created in air pressure between the valley and the coast. Larger differentials in air pressure mean stronger winds. The wind is speeded up even more as it is squeezed through the San Gorgonio Pass.
Maximum daily temperatures usually occur in the late afternoon and early evening in the Coachella Valley, creating a bigger difference in the air pressure and increasing wind speed as air funnels through the San Gorgonio Pass. The valley's windmills are very effective in creating energy just as it is needed most, when there is a greater demand for electricity to feed air conditioners in the Coachella Valley.
