Working with Timezones
Specifying Timezones
The Salesforce API expects the timezone to be specified when processing queries related to time fields.
By default, time columns are interpreted as being in GMT. For example:
SELECT Id FROM BusinessHours WHERE SundayStartTime = '18:00:00'
To specify a UTC offset time, alter the filter like this:
SELECT Id FROM BusinessHours WHERE SundayStartTime = '18:00:00+03:00'