What? Over 100? It's October!

Betty says,

It's hot on Thursday, it's in the high 90s most of the day and I was very surprised to learn that the highest temperature of the day was 100.    Then the forecast follows, it'll be 104 on Friday!

San Francisco is usually in the 60s all year round even during the summer, it's forecasted in the high 80s to low 90s for Friday, October 4. 

Is this a joke?  It's October!