No overlap — one side will join outside working hours
MDT (Denver)
AST (Riyadh)
00:00
09:00Working
01:00
10:00Working
02:00
11:00Working
03:00
12:00Working
04:00
13:00Working
05:00
14:00Working
06:00
15:00Working
07:00
16:00Working
08:00
17:00
09:00Working
18:00off
10:00Working
19:00off
11:00Working
20:00off
12:00Working
21:00off
13:00Working
22:00off
14:00Working
23:00off
15:00Working
00:00+1doff
16:00Working
01:00+1doff
17:00
02:00+1d
18:00
03:00+1d
19:00
04:00+1d
20:00
05:00+1d
21:00
06:00+1d
22:00
07:00+1d
23:00
08:00+1d
Working hours: 09:00–17:00 local. Green = both working.Purple = one side only.
Frequently Asked Questions
What is the difference between mdt and ast?
Mountain Daylight Time (mdt) is UTC-6 and Arabia Standard Time (ast) is UTC+3. The difference between them is 9 hours.
Where is mdt used?
Mountain Daylight Time (mdt) is used in USA and surrounding regions. The IANA timezone identifier is America/Denver.
Where is ast used?
Arabia Standard Time (ast) is used in Saudi Arabia and surrounding regions. The IANA timezone identifier is Asia/Riyadh. Note: ast is ambiguous and may refer to other timezones.
How do I convert mdt to ast?
Use the interactive converter above. Drag the time slider to any mdt time and the ast equivalent updates instantly. You can also type a time like "3pm" or "15:00" in the input bar.
MDT (Denver) is 9 hours behind AST (Riyadh). When it's noon in MDT (Denver), it's 21:00 in AST (Riyadh).
MDT (Denver) runs on America/Denver; AST (Riyadh) runs on Asia/Riyadh. Together they are 9 hours apart.
Business hours comparison
There is no business hours overlap between MDT (Denver) and AST (Riyadh) during standard working hours (9:00–17:00). Meetings would require one party to work outside normal hours.
Best call times between these locations
MDT (Denver) and AST (Riyadh) have no shared working window. These slots minimize out-of-hours disruption for both sides.
07:00 Denver / 16:00 Riyadh⚡ One side off-hours
⚠️ 2h before working hours in Denver
09:00 Denver / 18:00 Riyadh⚡ One side off-hours
⚠️ 2h after working hours in Riyadh
06:00 Denver / 15:00 Riyadh⚡ One side off-hours
⚠️ 3h before working hours in Denver
Working hours defined as 09:00–17:00 local time for each location.
Public holidays this year
MDT (Denver)8 holidays
Jun 19Juneteenth National Independence DaySOON
Jul 3Independence Day
Sep 7Labour Day
Oct 12Columbus Day
Oct 12Indigenous Peoples' Day
AST (Riyadh)
No upcoming public holidays this year.
MDT (Denver) and AST (Riyadh) — practical scheduling
Teams in MDT (Denver) (USA) and AST (Riyadh) (Saudi Arabia) deal with a 9-hour gap that pushes their working days apart. Real-time meetings always require someone to stretch outside the standard 9–5.
💡 Practical scheduling guidelines
⚡
A 07:00 meeting in MDT (Denver) means 16:00 in AST (Riyadh) (2h before working hours in Denver).
⚡
A 09:00 meeting in MDT (Denver) means 18:00 in AST (Riyadh) (2h after working hours in Riyadh).
⚡
A 06:00 meeting in MDT (Denver) means 15:00 in AST (Riyadh) (3h before working hours in Denver).
With no shared business hours, these slots distribute the scheduling burden as evenly as possible between both locations.
Avoid scheduling mistakes — especially around daylight saving changes. Use the ClockinSync Chrome Extension to instantly verify and compare both time zones directly in your browser, without manual calculations.
Need a specific time? Use the slider or type directly into the input bar — it understands "3pm", "15:30", and location-specific formats like "9am MDT (Denver)".