From Blaseball Wiki

Jazz is a weather condition introduced in Season 23. A game in Jazz weather will immediately switch to a random other weather condition.

It is possible for Polarity weather to occasionally switch to Jazz weather instead of the opposite polarity, accompanied by the message "The Band began to play.".

Game Log Text

A Riff opens.
馃幍 [scat] [weather] 馃幍

Observed Scat Syllables

Three to five of these syllables are strung together each time a Riff opens, e.g. "bip bop bee bip" or "shoo do bow".

  • ah
  • bah
  • bee
  • bip
  • boh
  • bop
  • boo
  • bow
  • da
  • dah
  • dee
  • do
  • doh
  • doo
  • la
  • louie
  • ooie
  • ooo
  • sha
  • shoo
  • ska
  • ski
  • skoo (as of Season 24)
  • wah

Observed Weathers

Jazz appears to be able to switch to any ongoing weather condition (i.e. not including Pre-Historic weathers or Sun 90), though Polarity - has not yet been observed. It is unknown whether Jazz weather can switch to itself.