Is there a way to use a drop down box as the criteria in vlookup. We have a
list of months and the corresponding days in the month. When someone selects
the month from a drop down list, the appropriate number of days should be
returned from the vlookup. The lookup is returning the wrong number of days
for the selected month.

Example

Drop down validation uses the months in column M. The drop down is in cell
D1.

Vlookup in F1 - VLOOKUP(D1,M8:N19,2)

Col M Col N Rows 8-19
October 21
November 22
December 23
January 21
February 20
March 23
April 21
May 22
June 22
July 21
August 23
September 22

As is, the vlookup returns 20 for July. Is there a way to fix the error.

Thanks