Junk bonds are the best indicator for risk appetite. See the relative chart of HYG vs TLT.
In the past a divergence of this ratio with SPY has been an early indicator of a fall in equities ahead. Currently there is no such indication. It is rising in tandem with the SPY. This indicates the bull market in equities is still alive and healthy. When this changes, we will alert you. Till then it is safe to be long in equities.