Editing Sonoma County, California (section)

===Climate===
[[File:DryCreekValley.jpg|right|thumb|Sonoma County's Dry Creek Valley]]

Sonoma County, as is often the case with coastal counties in California, has a great degree of climatic variation and numerous, often very different, microclimates.<ref>{{cite web |url=http://cesonoma.ucdavis.edu/hortic/sonoma_county_climate.pdf |title=Sonoma County Climatic Zones |access-date=November 30, 2007 |publisher=University of California Cooperative Extension |archive-url=https://web.archive.org/web/20070812154328/http://cesonoma.ucdavis.edu/hortic/sonoma_county_climate.pdf |archive-date=August 12, 2007 |url-status=dead  }}</ref><ref name="ucDavisClimate">{{cite web |url=http://cesonoma.ucdavis.edu/hortic/pdf/climate_location_data.pdf |title=Climate data for various locations in Sonoma, Napa, Mendocino, Lake and Marin counties, California |first=Rip |last=Forrey |access-date=November 30, 2007 |publisher=University of California Cooperative Extension Sonoma County |archive-url=https://web.archive.org/web/20070630163510/http://cesonoma.ucdavis.edu/hortic/pdf/climate_location_data.pdf |archive-date=June 30, 2007 |url-status=dead  }}</ref> Key determining factors for local climate are proximity to the ocean, elevation, and the presence and elevation of hills or mountains to the east and west. This is in large part due to the fact that, as throughout California, the prevailing weather systems and wind come normally from the Pacific Ocean, blowing in from the west and southwest, so that places closer to the ocean and on the windward side of higher elevations tend to receive more rain from autumn through spring and more summer wind and fog. This itself is partly a result of the presence of high and low pressures in inland California, with persistent high summer temperatures in the [[Central Valley (California)|Central Valley]], in particular, leading to low pressures, drawing in moist air from the Pacific, cooling into damp cool breezes and fog over the cold coastal water. Those places further inland and particularly in the lee of significant elevations tend to receive less rain and less, in some cases no, fog in the summer.

The coast itself is typically cool and moist throughout summer, often foggy, with fog generally blowing in during the late afternoon and evening until it clears in the later morning becoming sunny, before repeating. Coastal summer highs are typically in the mid to high 60s, warming to the low 70s further from the ocean.

Certain inland areas, including the Petaluma area and the Santa Rosa Plain, are also prone to this normal fog pattern in general.<ref name="ucDavisClimate" /> However, they tend to receive the fog later in the evening, the fog tends to be more short-lived, and mid-day temperatures are significantly higher than they are on the coast, typically in the low 80s F. This is particularly true for Petaluma, [[Cotati, California|Cotati]], and [[Rohnert Park, California|Rohnert Park]], and, only slightly less so, Santa Rosa, [[Windsor, California|Windsor]], and [[Sebastopol, California|Sebastopol]]. In large part, this results from lower elevations and the prominent [[Petaluma Gap]] in the hills between the ocean to the west and the Petaluma Valley and Santa Rosa Plain to the east.

Areas north of Santa Rosa and Windsor, with larger elevations to the west and further from the fog path, tend to receive less fog and less summer marine influence. Healdsburg, to the north of Windsor, is less foggy and much warmer, with summer highs typically in the higher 80s to about {{convert|90|°F|°C|abbr=on}}. Sonoma and the Sonoma Valley, east of Petaluma, are similar, with highs typically in the very high 70s F to {{convert|80|°F|°C|abbr=on}}. This is in part due to the presence of the Sonoma Mountains between Petaluma and Sonoma. [[Cloverdale, California|Cloverdale]], far to the north and outside of the Santa Rosa Plain, is significantly hotter than any other city in the county, with rare evening-morning fog and highs often in the 90s, reaching {{convert|100|°F|°C|abbr=on}} much more frequently than the other cities. Notably, however, the temperature differences among the different areas of the county are greatest for the highs during mid-day, with the diurnal lows much more even throughout the entire county. The lows are closely tied to the evening-morning cooling marine influence, in addition to elevation, bringing similarly cool temperatures to much of region.

These weather patterns contribute to high diurnal temperature fluctuations in much of the county. In summer, daily lows and highs are typically 30–40&nbsp;°F apart inland, with highs for Petaluma, Cotati, Rohnert Park, Santa Rosa, Windsor, and Sebastopol typically being in the very low 80s F and lows at or near {{convert|50|°F|°C|abbr=on}}. Healdsburg and the City of Sonoma, with similar lows, have even greater diurnal fluctuations due to their significantly warmer highs. On the other hand, the coast, with strong marine influence, tends to have low diurnal temperature fluctuation, with summer highs much cooler than the inland towns, typically 65–75&nbsp;°F, yet lows in the high 40s to low 50s F, fairly comparable to most inland towns.

These microclimates are evident during the rainy seasons as well, with great variation in the amount of rainfall throughout the county. Generally, all of Sonoma County receives a fair amount of rain, with much of the county receiving between about {{convert|25|in|mm|abbr=on}}, comparable to areas such as Sonoma and Petaluma, and roughly {{convert|30|in|mm|abbr=on}} normal for Santa Rosa. However, certain areas, particularly in the north-west portion of the county around the Russian River, receive significantly more rainfall. The [[Guerneville, California|Guerneville]] area, for example, typically receives about {{convert|50|in|mm|abbr=on}} of rain a year, with annual rain occasionally going as high as {{convert|70|in|mm|abbr=on}}. Nearby Cazadero typically receives about {{convert|72|in|mm|abbr=on}} of rain a year, many times has reached over {{convert|100|in|mm|abbr=on}} a year, and sometimes over {{convert|120|in|mm|abbr=on}} of rain in a year. The Cazadero region is the second wettest place in California after [[Gasquet, California|Gasquet]].<ref>{{cite web|url=http://abclocal.go.com/kgo/story?section=local&id=4058640|title=Rainiest Town In The Bay Area Up For Sale|access-date=December 13, 2007|last=Freedman|first=Wayne|date=April 5, 2006|publisher=[[KGO-TV]] News|archive-url=https://web.archive.org/web/20110521143346/http://abclocal.go.com/kgo/story?section=news%2Flocal&id=4058640|archive-date=May 21, 2011|url-status=dead}}</ref>

Snow is exceedingly rare in Sonoma County, except in the higher elevations on and around the [[Mayacamas Mountains]], particularly [[Mount Saint Helena]], and [[Cobb Mountain]], whose peak is in Lake County.<ref>{{cite web |title=Subsection M261Be Konocti Flows |publisher=U.S. Forest Service |url=http://www.fs.fed.us/r5/projects/ecoregions/m261be.htm |archive-url=https://web.archive.org/web/20110922101445/http://www.fs.fed.us/r5/projects/ecoregions/m261be.htm |archive-date=September 22, 2011 |access-date=February 22, 2014}}
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