CDT to HST Converter
Convert time between Central Daylight Time (CDT) and Hawaii Standard Time (HST)
Central Daylight Time (CDT)
Hawaii Standard Time (HST)
Time Difference
Hawaii Standard Time (HST) is 0 hours ahead of Central Daylight Time (CDT)
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Select Time
Quick Reference
| CDT | HST |
|---|---|
| 20:00 | 16:00 |
| 22:00 | 18:00 |
| 00:00 | 20:00 |
| 02:00 | 22:00 |
| 04:00 | 00:00 |
| 06:00 | 02:00 |
| 08:00 | 04:00 |
| 10:00 | 06:00 |
| 12:00 | 08:00 |
| 14:00 | 10:00 |
| 16:00 | 12:00 |
| 18:00 | 14:00 |
Top 10 Most Common Time Zones
| Abbreviation | Full Name | UTC Offset | Typical Use |
|---|---|---|---|
| UTC | Coordinated Universal Time | UTC ±0 | Global reference standard (servers, logs, APIs) |
| EST / EDT | Eastern (US) Time | UTC −5 / −4 | New York, Toronto — North American business hub |
| CST / CDT | Central (US) Time | UTC −6 / −5 | Chicago, Dallas — US central business region |
| PST / PDT | Pacific (US) Time | UTC −8 / −7 | San Francisco, Los Angeles — tech industry standard |
| GMT / BST | Greenwich Mean / British Summer Time | UTC 0 / +1 | UK, used globally as a reference with UTC |
| CET / CEST | Central European (Summer) Time | UTC +1 / +2 | Paris, Berlin, Amsterdam — EU business core |
| IST | India Standard Time | UTC +5:30 | India — major IT & outsourcing region |
| CST | China Standard Time | UTC +8 | Beijing, Shanghai — East Asia business hub |
| JST | Japan Standard Time | UTC +9 | Tokyo — finance & tech hub |
| AEST / AEDT | Australian Eastern (Daylight) Time | UTC +10 / +11 | Sydney, Melbourne — APAC regional business |
Why Time Zone Abbreviations Are Ambiguous
Unlike standardized identifiers (like America/New_York or Europe/London from the IANA tz database), abbreviations such as "CST" or "IST" are not globally unique. They can refer to different time zones depending on context — country, region, or even time of year (due to daylight saving time).
Common Ambiguous Time Zone Abbreviations
| Abbrev. | Common Meaning(s) | UTC Offset | Region(s) |
|---|---|---|---|
| CST | Central Standard Time / China Standard Time / Cuba Standard Time | UTC−6 / UTC+8 / UTC−5 | North America, China, Cuba |
| IST | Indian Standard Time / Irish Standard Time / Israel Standard Time | UTC+5:30 / UTC+1 / UTC+2 | India, Ireland, Israel |
| AST | Atlantic Standard Time / Arabia Standard Time | UTC−4 / UTC+3 | Caribbean, Canada, Middle East |
| PST | Pacific Standard Time / Philippine Standard Time | UTC−8 / UTC+8 | North America, Philippines |
| EST | Eastern Standard Time (North America / Australia) | UTC−5 / UTC+10 | North America, Australia |
✅ Best Practice
To avoid ambiguity, always:
- Use IANA tz identifiers — e.g.,
America/New_Yorkinstead of "EST" - Specify UTC offset explicitly — e.g.,
UTC−5when abbreviations must be used - Include the full timezone name — e.g., "Eastern Standard Time (EST)" with UTC offset
Related Time Zone Conversions
About CDT to HST Time Conversion
Converting time between Central Daylight Time (CDT) and Hawaii Standard Time (HST) is essential for coordinating between the US Central region and Hawaii during summer months (March to November). CDT is UTC-5 (daylight saving time, observed March to November), while HST is UTC-10 (year-round, Hawaii does not observe daylight saving time). CDT is consistently 5 hours ahead of HST. This is different from winter coordination when the Central region observes CST (UTC-6), which is only 4 hours ahead of HST.
This conversion is crucial during the summer season for businesses operating between Chicago, Dallas, Houston, and Hawaii. Tech companies, tourism operations, government agencies, and enterprises coordinating mainland central region and island operations rely on accurate time conversions during daylight saving season. Understanding that Hawaii Standard Time remains constant throughout the year makes scheduling easier for long-term projects spanning both seasons. The consistent 5-hour difference during CDT season (compared to the variable 4-5 hour difference when accounting for both CST and CDT) simplifies summer business operations across the mainland central region and islands.
Common Use Cases for CDT to HST Conversion
Business & Work
- Scheduling summer calls between Chicago headquarters and Hawaii branch offices
- Coordinating business operations between Central region and Hawaiian locations during peak season
- Managing tourist operations and hospitality services during summer travel season
- Planning summer conference calls for companies with presence in both regions
Personal & Travel
- Coordinating with family and friends in Hawaii during summer months
- Planning summer travel between Central region and Hawaiian destinations
- Scheduling virtual meetings with Hawaii-based relatives during daylight hours
- Arranging online collaboration with Hawaii-based colleagues during business season
Time Zone Information
Central Daylight Time (CDT)
- UTC Offset: UTC-5
- IANA Timezone: America/Chicago
- Daylight Saving: Daylight saving time (second Sunday in March to first Sunday in November)
- Major Cities: Chicago, Dallas, Houston, Kansas City, St. Louis, Memphis
- Coverage: Central United States and Canada (summer months)
Hawaii Standard Time (HST)
- UTC Offset: UTC-10
- IANA Timezone: Pacific/Honolulu
- Daylight Saving: No daylight saving time (consistent year-round)
- Major Cities: Honolulu, Hilo, Kailua, Maui, Kauai
- Coverage: All Hawaiian islands (consistent year-round)
Quick Reference: CDT to HST
Remember: CDT is always 5 hours ahead of HST during daylight saving time (March-November). When daylight saving time ends (first Sunday in November) and CDT becomes CST, the difference decreases to 4 hours. Hawaii does not observe daylight saving time.
Frequently Asked Questions
What is the time difference between CDT and HST?
Central Daylight Time (CDT) is UTC-5, while Hawaii Standard Time (HST) is UTC-10. CDT is 5 hours ahead of HST. When it's 11:00 AM in Chicago (CDT), it's 6:00 AM the same day in Honolulu (HST).
When is CDT active and how does it affect Hawaii coordination?
CDT is observed from the second Sunday in March to the first Sunday in November. During this period, the Central region is 5 hours ahead of Hawaii. From November to March, when the Central region observes CST (UTC-6), the difference is only 4 hours. This makes summer coordination (CDT season) have a larger time gap than winter coordination.
Does Hawaii observe daylight saving time like CDT does?
No, Hawaii does not observe daylight saving time. Hawaii Standard Time (HST) remains UTC-10 year-round. This is why the time difference between Hawaii and the mainland varies - the mainland changes its clocks twice per year while Hawaii stays constant. CDT is specifically the summer offset for the Central region.
What major cities are in CDT and HST timezones?
CDT covers major Central region cities including Chicago, Dallas, Houston, Kansas City, St. Louis, and Memphis during summer months. HST covers all Hawaiian islands with major cities being Honolulu, Hilo, Kailua, Waihuku, and Kaneohe. These regions represent the US Central region during daylight saving season and the Hawaiian Islands.
What are the best times to schedule calls between CDT and HST regions?
The 5-hour difference during CDT season is significant but still manageable. Early morning CDT times (8-9 AM) correspond to very early morning HST (3-4 AM), and late morning CDT (10 AM-12 PM) corresponds to early morning HST (5-7 AM). Late afternoon CDT (3-5 PM) aligns well with late morning/midday HST (10 AM-12 PM), making this an ideal window for summer business coordination.
How does summer (CDT) coordination differ from winter (CST) coordination with Hawaii?
During summer (March-November, CDT season), the Central region is 5 hours ahead of Hawaii, creating the largest time gap for mainland-Hawaii coordination. During winter (November-March, CST season), the difference is only 4 hours, providing better overlap for business hours. Many businesses adjust their summer schedules to account for the larger time difference, while winter offers more flexibility for overlapping work hours.
Pro Tips
- • CDT is always 5 hours ahead of HST during summer months (March-November).
- • When daylight saving time ends (first Sunday in November), CDT becomes CST and the difference decreases to 4 hours.
- • Early morning CDT times (8-10 AM) correspond to early morning HST times (3-5 AM), making them ideal for urgent business operations.
- • Hawaii does not observe daylight saving time, so HST is consistent year-round while CDT changes once per season.
- • For long-term projects spanning both seasons, account for the time difference change when CDT transitions to CST in November.
- • Late afternoon CDT (3-5 PM) aligns well with late morning/midday HST (10 AM-12 PM), providing excellent overlap for summer business calls and coordination.
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