Both locations are within waking or working hours.
A Time Zone is a region of the globe that observes a uniform standard time for legal, commercial, and social purposes. Standard time zones are defined by offsets from Coordinated Universal Time (UTC) or Greenwich Mean Time (GMT).
Time zone boundaries tend to follow country and subdivision borders rather than exact meridians. Many regions observe Daylight Saving Time (DST) during summer months, changing offsets by adding 1 hour.
Planning international webinars or conference calls across boundaries (e.g. EST to GMT or PST to JST) requires finding overlapping hours. Hours between 9:00 AM and 5:00 PM local time represent typical corporate working windows.