This is probably basic stuff.

I presently use COUNTIF to count the number of instances of the letter
"x" or "o" in a column:
=COUNTIF(B:B,"x")

I need to find totals of one condition in a column when another column
has another condition.

In the following data range, for example, I might need to find the
number of times "x" appears in column B during a particular month, like
February, or during a certain time of day.

A B C
January 4 x morning
January 4 o afternoon
January 12 o morning
January 15 o morning
January 15 x afternoon
February 2 x morning
February 2 x morning
Ferbrary 4 o morning
February 10 x morning

I might also like to count, for example, the number of times "x"
apppears in the morning in February.

Please write out examples. My date format is MM-DD-YY.