<P> Summers are warm to hot , and nearly completely dry . The summer temperature pattern usually begins in late June or early July , and lasts through September or October , although it may start as early as late May . In August , the average high / low at the University of Southern California downtown campus are 84.8 ° F ( 29.3 ° C ) and 65.6 ° F ( 18.7 ° C ) . The same figures at the LAX airport , approximately 12 miles ( 19 km ) to the southwest and near the ocean , are 76.6 ° F ( 24.8 ° C ) and 64.2 ° F ( 17.9 ° C ) . However , temperatures across the region sometimes exceed 90 ° F ( 32 ° C ) during the summer . This happens when an atmospheric high - pressure area becomes dominant over the Great Basin of Nevada and Utah ( a frequent occurrence ) , and the resulting offshore flow of the atmospheric air mass shuts off the normal coastal sea breeze in Los Angeles . July , August and September are the hottest months , with September holding the all - time record of 113 ° F ( 45 ° C ) . Skies are nearly constantly sunny , unless interrupted in late spring and early summer by the June Gloom pattern , which is unpredictable year - to - year . The North American Monsoon can bring occasional thunderstorms and high humidity to Los Angeles in the summer and early fall . </P>
when does the weather warm up in los angeles
usually begins in late June or early July