Well, I would say that summer has indeed come and has been around for a little while now, but the title of this song is "Natsu ga Kuru" (Summer Will Come) by one of the singing representatives of the season, Maki Ohguro（大黒摩季）. This was her 8th single from April 1994 and it's that racing pop tune with some Latin percussion that I would always expect from Ohguro.
The thing is, though, despite the title and the good feelings of the hot season within the arrangements, "Natsu ga Kuru" isn't really about having fun in the good ol' summertime. Written and composed by Ohguro, the lyrics are actually a friendly advice column about not letting any doubts generated by oneself or surrounding people about Mr. Right get in the way of a potentially happy life together.
I'm surprised that the song wasn't a theme for some comedy-drama on one of the private TV networks. However, it did serve as the opening theme for the TBS music program, "Countdown TV" and as the commercial song for Sapporo Ice Lager, a most appropriate drink for "Natsu ga Kuru". The song became a million-seller peaking at No. 2 on the Oricon weeklies. It also joined another Ohguro hit, "Anata dake Mitsumeteru"（あなただけ見つめてる）on her 4th album "Eien no Yume ni Mukatte" (永遠の夢に向かって...Facing the Eternal Dream) which came out in November 1994. That release quickly hit No. 1 in its first week. For the yearly rankings, it rapidly became the 13th-ranked album for 1994 and hung around for another year to rank in at No. 25.