One of the best times to use chlorine is after a heavy rainstorm. Chlorine will help in breaking down any bacteria that the storm has stirred up.  Another good time to use chlorine is when you are about to have a pool party or when you've just finished hosting one. This assures that your pool stays clean and safe for everyone involved! Moreover, while applying chlorine, you have to keep in mind that it should not be exposed to direct sunshine. This means the appropriate time of the day to apply chlorine in your pool area is in the early mornings and late evenings.