Yes, by default the time zone is set at PST. But you can change it and set it according to your timezone from Settings.
To change your timezone:
- Click on Settings -> Change Timezone.
- Set up your timezone accordingly.
- Click the Submit button.
Your timezone will be set!
Note: The timezone you set here will be for all of your accounts you connect and for not just any particular account. The posts will go out according to this timezone only.