Mvua : Tofauti kati ya masahihisho

Asili ya mvua ni [[mvuke]] wa [[maji]] katika [[angahewa]]. Kiasi cha mvuke hewani kutajwa kama [[gramu]] za maji kwa [[kilogramu]] ya [[hewa]]. <ref>{{cite web|author=Steve Kempler|year=2009|url=http://daac.gsfc.nasa.gov/PIP/shtml/atmospheric_water_vapor_or_humidity.shtml|title=Parameter information page|publisher=[[NASA]] [[Goddard Space Flight Center]]|accessdate=2008-12-27 |archiveurl = https://web.archive.org/web/20071126083414/http://daac.gsfc.nasa.gov/PIP/shtml/atmospheric_water_vapor_or_humidity.shtml |archivedate = November 26, 2007}}</ref><ref>{{cite book |url=http://www.atmos.washington.edu/~stoeling/WH-Ch03.pdf| page=80|accessdate=2010-01-30|date=2005-09-12|author=Mark Stoelinga|title=Atmospheric Thermodynamics|publisher=[[University of Washington]]|archiveurl=https://web.archive.org/web/20100602004341/http://www.atmos.washington.edu/~stoeling/WH-Ch03.pdf|archivedate=2010-06-02}}</ref> Kiasi cha [[unyevu]] (yaani maji) katika angahewa huitwa [[unyevuanga]]. Uwezo wa hewa kushika unyevuanga hutegemea [[halijoto]] ya hewa. Hewa [[baridi]] ina uwezo mdogo kutunza unyevu ndani yake, kiasi kinaongezeka kadiri halijoto iko juu zaidi. Pale ambapo hewa inafikia hali ya kushiba unyewu unaanza kutonesha yaani matone kutokea. Wakati matone yanafikia kiwango fulani cha [[uzito]] yanaanza kuanguka chini yaani mvua inaanza kunyesha.