NY Times Crossword
Eric Berlin - Jan. 20, 2004

Each answer to the clues below is a compound word or two-word phrase. The first halves of the answers follow a certain pattern. Can you determine what it is?

Week of 100 degree plus weather
Repel, as an attack
Harbor event, perhaps
Eat quickly
Dark, heavy type
Week of 40 degree weather

Answers:

Heatwave
Beat back
Boat show
Bolt down
Boldface
Cold snap

The first halves of the answers form a word ladder - going from HEAT to COLD by changing one letter at a time.