> ## Documentation Index
> Fetch the complete documentation index at: https://help.maestra.io/llms.txt
> Use this file to discover all available pages before exploring further.

# How a Customer's Time Zone Is Determined

Time zone is one of the basic fields on a customer profile. Having it lets you personalize communications — sending campaigns that land at the right local time for each recipient.

## How the time zone is determined

Maestra picks the customer's time zone from the following sources, listed from highest priority to lowest:

<Steps>
  <Step title="Explicit transmission via an operation or import">
    A time zone passed in directly through an API operation or a data import.
  </Step>

  <Step title="Mobile app tracker">
    Time zone reported by the mobile app tracker.
  </Step>

  <Step title="JS tracker (device system time)">
    Time zone inferred by the JS tracker from the device's system time.
  </Step>

  <Step title="Customer zone">
    The time zone configured for the customer's zone, if one is set for that zone.
  </Step>

  <Step title="Mobile number code">
    Time zone derived from the country code of the customer's mobile phone number.
  </Step>
</Steps>

Higher-priority sources always override lower-priority ones.

<Note>
  Example: a customer has a time zone filled in based on their zone. They then visit your site, and the device's local time differs from what's in the profile. The time zone on the profile will change, because tracker data is higher priority than the customer's zone.
</Note>

## Related

* Best time to send email and SMS campaigns — based on campaign performance data from 60 Maestra customers.