The seasonal start date marks a time
of year where a set of per diem rates is valid. It differs from the
effective date because the seasonal start date is just a month and a day (like
Jan. 26 instead of Jan. 26, 2008). Basically the
per diem rates change
throughout the year, and the seasonal start date is the beginning date for a
change in per diem rates. It is important to note the
effective date,
expiration date,
seasonal start date, and
seasonal end date
when calculating the
per diem deduction.
For pilots and flight attendants,
this is important because the date of a layover matters just as much as where
the layover was when it comes to calculating a per diem deduction.
Ottawa, Canada
is a good example of a city that shows how per diem rates can change
throughout the year, which is why a
per diem
calculator is so useful in calculating the
M&IE deduction.