Why is the US election on Tuesday November 8?

Washington - It is always the first Tuesday after the first Monday to avoid the election falling on November 1st.

On Tuesday, November 8, Americans will decide whether Republican Donald Trump or Democrat Hillary Clinton will be handed the keys to the White House.
The election is in November because America was a predominantly agrarian society and November was the quietest for rural workers. 
It is always traditionally on a Tuesday to allow people living in rural areas time to travel to towns and cities to vote, removing the need to travel on a Sunday. 
US Election 2016: All you need to know
 
It is always the first Tuesday after the first Monday to avoid the election falling on November 1st. This was to avoid clashing with All Saints Day and the day when businessmen traditionally did their accounting from the previous month.
The US electoral college explained
 
Who will win the US Election 2016? Vote here

Everything you need to know about US Election 2016:

When is election day in the US?
When will the next US President be announced?
The US electoral college explained
Results: Election projection
What are swing states?
Hillary Clinton vs Donald Trump
 Who won the debates?
Trump-Clinton policies: Stand on key issues

• Battle For White House