Suika (水夏) is a Japanese adult visual novel developed by Circus and was first released on July 27, 2001 for the PC as a CD-ROM, followed by a DVD-ROM release on August 31, 2001. It was followed by two all-ages consumer ports for the PlayStation, retitled as Water Summer, and the Dreamcast on July 18, 2002, which was subsequently followed by an all-ages version for the PC, released on July 25, 2003. An expanded version, entitled Suika A.S+ (水夏A.S+), was released in Japan on September 24, 2004 with the adult content found in the original version, followed by a European release on April 25, 2009, and was again ported to the PlayStation 2, entitled Suika A.S+ Eternal Name (水夏A.S+ Eternal Name), released on August 30, 2007 with the adult content removed. The gameplay in Suika follows a linear plot line, which offers pre-determined scenarios and courses of interaction, and focuses on the appeal of the main female characters.

Suika has made several transitions to other media. A light novel was published by Paradigm in November 2001 and a set of four drama CDs were produced between August 2002 and January 2003. A four-episode adult original video animation created by Moon Rock was released between February 25, 2003 and June 25, 2003 as three DVDs containing one episode each, followed by a DVD box-set released on April 25, 2004 containing an extra episode, and was subsequently licensed for sale in North America under the title Wet Summer Days by Kitty Media.