So I hesitate to put this up as I disagree with the present direction of WOTC. However, I am glad there is a community with Ed Greenwood and others who passionately care for the story and wonderful world that was created.
Basically the map originated from the Interactive Forgotten Realms Atlas, a global map. From there I just sectioned it off into 24 sections. The +12/-12 overlap and are basically the same line.... so the edges of the map overlap. This was a work in progress.
Some things I didn't get a change to mention, but keep in mind the world is a globe and this map's scale is based at the equator. As you move toward the poles, the map scale should be adjusted to accommodate the change in distance (things are closer as you move toward the poles). It may be helpful to use local maps.
Now given that in the past and present, there are Spelljammers.... the former nation of Netheril, Wa, Shou Lung, and the Imperial Elven Armada should have awareness of time zones. Also keep in mind that the Sage of Shadowdale does have a satellite in orbit as well, perhaps with some observations of the globe.
Why even care about timezones? Well magic of course! One of the questions that bothered me is when you are using portals and teleportation over vast distances. Does the spell just assume a general localized time or does it work realistically? If I am on the Sword Coast and travel to Thay, there is a three hour difference. My sunset is not the same as that sunset. Given that magic-users often state Moonrise, Sunrise, Sunset, Midnight... and so on....you do need timezones. If we are casting spells with specific points based on the Sun and Moon... I should no when it will occur. Yet that is just me.
Time Zones of the Realms
The northern hemisphere enjoys 13 hours of sunlight and 11 hours of night during the summer months, 10 hours of sunlight and 13 hours of night during the winter months, and 12 hours of sunlight and 12 hours of night during Spring and Autumn. The nations of Anchorome, Evermeet, Nimbral, Lantam , Moonshaes, Faerun, Hordelands, Norther Shou Lung, Wa, Korozuka, and Korya
The equatorial zone of Abeir-Toril enjoys exactly 12 hours of sunlight and 12 hours of night. The nations of the Maztica, Northern Katakasha, Shining South, Zakhara, mainland Kara-Tur, and Osse are found within these zone.
The southern hemisphere enjoys the same amount of day and night as the northern hemisphere, but the seasons are alternate. When the northern hemisphere experience summertime, the southern hemisphere experiences winter. The nations of southern Katashaka, southern islands of Zakhara, and southern coastal Osse are within this zone.
When the sunrise happens on the west coast of Maztica, it is an hour before sunset in Laothon.
Western Time Zone
This area includes
-Anchorome (North-Western)
Anchorome Time Zone
This area includes
-Azupoi
-Katashaka (West Coast)
Nexalan Time Zone
This area includes
-Anchorome (East Coast)
-Maztica
-Lopango
-Katashaka (Central)
Trackless Time Zone
This area includes
-Evermeet (East Coast)
-Tabaxiland (West Coast)
-Katashaka (East Coast)
-Nimbral (West Coast)
Moonshae Time Zone
This area includes
Regions
-Sword Coast North
*Luksan
*Neverwinter
Nations
-Icewind Dale Confederation
*Bremen
*Bryn Shander
*Caer-Dineval
*Caer-Konig
*Dougan’s Hole
*Easthaven
*Good Mead
*Lonelywood
*Targos
*Termaline
-Gundarlun
-Rauthym
-Moonshae Isles
-Nelanther Isles
-Lantan
*Anchoril
*Sambar
*Sundrah
-Nimbral
*Ormen
*Tethmor
*Nimsur
*Rauthhaven
-Chult
*Mezro
*Port Castigliar
*Port Nyanzaru (Amn Colony/Independent)
-Samarach
*Samargol
Sword Coast Time Zone
Regions
-The Savage Frontier
-The High Forest
-The Sword Coast
*Baldur’s Gate
*Daggerford
Nations
-Luruar “Confederacy of the Silver Marches”
*Citadel Adbar
*Citadel Felbarr
*Everlund
*Mithrall Hall
*Silverymoon
*Sundbar
-Waterdeep
-Evereska
-Najara
-Elturgard
-Amn
-Tethyr
-Calishman
-Thindol
-Tashalar
Sea of Fallen Stars Time Zone
This area includes
-Vaasa
-Damara
-Impiltur
*Dilpur
*Hlammach
*Ilmwatch
*Lyrabar
*Sarshel
-Thar
-Zhentil Keep
-Cormanthor
-Dalalands
-The Vast
-Sembia
-Cormyr
-Turmish
-Hlondeth
-Chondath [Akanul]
-Sespech
-Erlkazar
-Lapaliiya
Thay Time Zone
This area includes
-Narfell
-Rashemen
-Algarond
-The Great Dale
-Thesk
-Thay
-Mulhorand [High Imaskar]
-Unther [Tyrmanther]
-Chessenta
-The Great Rift
-Murghom
-Luiren
-Veldorn
-Estagund
-Dambrath
-High Desert (Zakhara)
-Orkoth
-Songfarla
-Deep Imaskar
Horse Lords Time Zone
This area includes
-Yaimunnahar
-Ra-Khati
-Sempadan (Western)
-Semphar
-Var The Golden
-Siremun
-Durpar
-Ulgarth
-Haunted Lands (Zakhara)
Dragonwall Time Zone
Shou Lung
Tabot
Petan
Khazari
Mahasarpha
Tu Lung (Western)
Mahasiswa
Wa Time Zone
Wa
Koryo
Kozakura
Tu Lung
Shou Lung (South East)
Tu Lung
Laothan
Purang
Malatra
Kuong
Bawa
Bertan