Time, Calendar, and Tendays

In the Forgotten Realms the year is split into twelve months. Each month has 30 days made up of 3 Tendays. Weeks in Forgotten Realms are ten days long. Thus the term Tenday. Each season is separated by a festival. The march of time is measured on the Calendar of Harptos.

Midwinter (also known as DeadWinter)
Midwinter marks the halfway point through Winter and is celebrated by rich folk and nobles alike, but more common folk see it as a bitter reminder that Winter is only half way over.

Greengrass
The official beginning of Spring is a day of peace and rejoicing.

Midsummer
A time of feasting, music, and love. Deities themselves participate in the festivities by ensuring good weather. Bad weather on Midsummer is an omen of extremely ill fortune.

Highharvestide
This holiday of feasting celebrates the Autumn harvest and also marks a time of journeys. Emissaries, pilgrims, adventurers, and everyone else eager to make a speed traditionally leaves on the day after Highharvestide. Often celebrations begin a few days before Highharvestide and culminate on the special day in a big bash.

The Feast of the Moon
This special day celebrates ancestors and the honored dead.

Shieldmeet
Is a special day that comes about every four years. It is like a leap day. It takes place immediately following Midsummer the next day and extends the celebrations. It is a day of tournaments, duals, and trials of magical prowess.

Time is broken down into time periods. Time periods break the day into 12 equal parts and can be identified as follows:

Dawn (~6am) marks the beginning of the day
Morning (~8am) time for breakfast
MidMorning (~10am)
Highsun (~12noon) time for lunch
Afternoon (~2pm)
Late Afternoon (~4pm)
Sunset (~6pm) time for dinner, and sun is setting
Evening (~8pm)
Night (~10pm) time for bed
Midnight (~12 mid)
Moondark (~2am)
Night's End (~4am)

When planning watches use the time periods to mark the watch. Also travel will be marked in Time periods. It is customary to sleep for 4 time periods from Night to Dawn.