Landslides and Leeches?

After Steve and I decided on taking the great escape, traveling for 6 mos. from June-Dec, we quickly put together a list of places that we always wanted to go. We studied the very outdated globe that Steve has (Hello Russia and Czechoslovakia) and we determined that it made sense to start off in Nepal and work our way down through Southeast Asia through Vietnam, Laos, Cambodia, Thailand, Malaysia, and Indonesia and then hop over to Australia and NZ before we head home. After cracking open the first set of travel books from the library (we checked out 9!), one of the first paragraphs I read was "Mid-June to September is the least popular time to visit Nepal as it usually rains every day, and the trails and roads are muddy and plagued with landslides and leeches." Hmm...doesn't sound too promising of a jumping off point. Any one out there have any tips on traveling in Nepal in June-July? Are we talking little long grain rice sized leeches or pinky finger sized hoovers?