The server Haven uses a slightly modified Calendar of Harptos (which is the more or less standard Calendar for the Forgotten Realms) to better match our real world calendar. (The rest of of Faerun does too in Haven's version of this world.)

Harptos month is three Ten-day (30 days) long. We pretty much ignore the ten-day for our familiar weeks. Festivals are inserted in between on occasions (kind of like our 31rst, so I moved a few of them to line them up).

I sort of ignore the difference with the Feb calendar. Two days disappear out of Alturiak and become the holidays Passionfest and All Hallow's Eve (see below).

Dates for these festivals would be:

• Hammer: January
  
• Midwinter (January 31)
  
• Alturiak : February
  
• Shieldmeet every four years (Feb 29)
  
• Ches: March
  
• Spring Equinox on Ches (March) 19
  
• Greengrass between Ches 30 and Tarsakh 1 (March 31)
  
• Tarsakh: April
  
• Mirtul: May
  
• Passionfest Holiday between Mirtul 30 and Kythorn 1 (May 31) (non-canon)
  
• Kythorn: June
  
• Summer Solstice on Kythorn (June) 20
  
• Flamerule: July
  
• Midsummer between Flamerule 30 and Eleasias 1 (July 31)
  
• Eleasias: August
  
• Highharvestide between Eleasias 30 and Eleint 1 (August 31)
  
• Eleint: September
  
• Autumn Equinox on Eleint 21
  
• Marpenoth: October
  
• Starfall, 22nd day of Marpenoth
  
• All Hallow's Eve (October 31) (non-canon)
  
• Uktar : November
  
• Nightal: December
  
• Feast of the Moon between Nightal 30 and Hammer 1 (December 31)