CIDC-FM

The Orangeville area was struck by a massive F4 tornado on May 31, 1985, and the community felt it did not receive adequate warning. As such, an application was made to the Canadian Radio-television and Telecommunications Commission (CRTC) for a radio station to serve Orangeville. CRTC approval was given for the station on September 10, 1986.[2] The station's frequency allocation was moved from Guelph to Orangeville to allow for the service. CIDC was launched on May 1, 1987 on 103.5 FM with an ERP of 50,000 watts from a site located northwest of the town. The height of the hill (527.3 m) and tower (98.1 m) made the station antenna (0.6 m) higher above sea level than the CN Tower. The format carried on the station was 70's/80's hits and was branded as DC 103.5.

Original Z103.5 logo

On September 28, 1994, the CRTC approved the ownership transfer of Dufferin Communications from its shareholders to CKMW Radio Ltd., operator of Brampton multicultural station CIAO (AM). The station was branded Hot 103.5 in February 1995 (later calling it "Hot 103 dot 5"), playing only dance music. The station then began adding more R&B and pop tracks to its Top 40/dance playlist in February 1998, and was renamed Hits 103.5.

On July 28, 2000, approval was given to relocate the transmitter site from 6 km west of Orangeville town hall to 11 km east of Orangeville town hall and decrease the station's power from 50,000 watts to 30,700 watts.

In late December 2000, the station was renamed in imitation of New York City station WHTZ and became known as Z103-Dot-5 (pronounced "zee"), with the slogan "The Hit Music Channel", though the CIDC call letters were retained. The slogan was later changed to simply "Today's Hit Music".

Until the summer of 2006, Z103.5 was the only radio station in Canada that played dance music since CING-FM changed formats in 2001. It was the only Top 40 station left in Toronto after CJAQ-FM became Jack FM in 2003. For a brief period in 2001, CKDX-FM also played dance music but poor ratings led it to switch to an oldies format.

In the summer of 2006, Evanov launched a new station in Halifax, Nova Scotia patterned after CIDC. It used the Z103.5 moniker but featured a different logo and slogan, although it continued to use the dot on its branding until 2010, when it was changed to match CIDC's logo, except the ".5" ("Dot-5") was omitted. It was also at that time when Evanov phased out dots and points from all of its station IDs, especially for its Jewel radio stations. In January 2012, the Halifax station relaunched their Top 40/Dance format and began patterning their direction after its sister station in Winnipeg, CHWE, who uses the moniker "Energy 106." However, while the Winnipeg station continues to do well, the Halifax outlet would see their fortunes take a downturn in ratings and format changes that resulted in their flip to Country in September 2015.

By 2009, CIDC dropped the "dot" from its branding, referring the station as "Zee 103-5" and unveiling a new slogan, "All The Hits". Rival CKFM-FM switched from adult top 40 to contemporary hit radio due to high airplay on top-played singles, while CIDC-FM tweaked its format by adding some adult top 40 singles, such as Bon Jovi's What Do You Got?. Rival CKIS-FM dropped their rhythmic lean and went more mainstream in February 2011. At that same time, CIDC did the reverse: from mainstream to a rhythmic-lean, although it still plays a small percentage of dance music, which was slightly increased by 2015. Most non-top 40 dance hits remain at the station, although they are classics. It continues to report on Mediabase & Nielsen BDS as a contemporary hit radio. As of the summer of 2012, the station's slogan is "#1 For Hit Music", following the other Top 40 stations in Toronto, KiSS 92.5 and 99.9 Virgin Radio, which both claim to be "Toronto's #1 Hit Music Station!" As of 2016, CIDC reverted to the slogan "All The Hits."

Despite the decrease in dance music, the station's highest-rated program continues to be The Drive @ 5 Street Mix with DJ Danny D. The show is mixed live with vinyl records and Compact Discs. In 2000, the show started out as a 30-minute Friday afternoon mix, but soon expanded into a 1-hour set. By 2004-2005, the set was so popular that Z103.5 introduced the "Drive @ 5" five times a week. Recently, as of 2008, high-profile guest DJ's have started to mix live for the Drive @ 5 on several occasions including David Guetta, Tiesto, and Armin van Buuren (his show A State of Trance can be heard Sunday nights on this station). The station also had a Saturday Night edition of the "Drive @ 5 Street Mix" for a time. A similar show, The Power Mix with DJ Spence Diamonds, used to air three nights a week (Wednesday, Thursday, and Friday nights). The show, which featured urban music, was cut in fall of 2007. In 2011, the station introduced a mixshow during the lunch hour, dedicated to hits from the 1980s, 1990s, and early 2000s, called the Wayback Lunch.

The station aired some programming hosted by Canadian DJ Chris Sheppard in the mid-1990s to the early 2000s, including Pirate Radio and Groove Station.

Z103.5 also had a weekly show on Sundays called the Freestyle Frenzy, hosted by Z103.5 veteran Tony Monaco. It was solely a show of freestyle music and mixes. It aired from June 4, 1995, to January 2004, and was replaced with Ryan Seacrest's American Top 40 countdown. As of the summer of 2008, that show was removed from the schedule. CKFM-FM later picked up the show after its relaunch as Virgin Radio.

MC Mario also previously held regular Sunday programming called "The Mixdown" which ran for a full hour in the afternoon. MC Mario presented the hits of the week and new house and dance music that usually wasn't able to be heard on most Canadian stations. His Mixdown is still widely heard in Montreal and around the world. The Mixdown was last presented on Z103.5 in December 2004. There were large programming changes in 2005.

Despite rumours that CIDC has dropped dance music from its playlist, they continue to be the leading mainstream radio station in North America for dance music. With dance music making up approximately 20-30% of their playlist and overall programming, (which includes dedicating a full hour weekdays to the dance/electronic music genre during the Drive @ 5 Streetmix), these rumours could not be further from the truth. They boast an excellent relationship with various dance music labels, including North America's biggest electronic/dance label, Ultra Records. This has allowed them to feature some of the world's biggest DJs during the Drive @ 5 Streetmix, such as Tiësto, David Guetta, Armin Van Buuren, Ferry Corsten, Benny Benassi and special appearances by Paul Van Dyk and other world-renowned DJs in various timeslots.

Currently, the station competes with fellow Top 40 stations CKFM-FM and CKIS-FM, urban station CFXJ-FM, and to a lesser extent, hot AC station CHUM-FM.

The station annually hosts a number of live concert events. Past and present concerts include the Hot Rush (created in 1993 as Energy Rush, now Summer Rush), Euro-Freestyle Invasion (now Euro Invasion), and Partymania. Most of the concerts are sold-out because they are mostly filled with performances by dance artists that usually don't get much publicity. Its sister station in Halifax also started holding a similar Summer Rush concert in 2007, usually around the same time as its Toronto sibling.

The Summer Rush has been held at various venues over the years, including the Molson Amphitheatre at Ontario Place, Polson Pier (previously known as The Docks), and, more recently, the Kingswood Theatre at Canada's Wonderland. Typically, venues have changed every three to five years. There have been over a hundred artists featured from Europe, South America, USA, and Canada, including Real McCoy (twice - 1997 and 2009), Culture Beat (twice - 1993 and 2004) Cascada (three times - 2004, 2006, 2008), DHT, B4-4 (a crowd favourite), Joee, Sarina Paris, Len, Boomtang Boys, Snap!, Waldo's People, Do (singing DJ Sammy's "Heaven"), Haiducci, DC Project, Jam & Spoon, Elissa, Stevie B, Ian Van Dahl, Sash!, Rupee, Kevin Lyttle, Jesse McCartney, JoJo, Elise Estrada, Basshunter and Daddy Yankee.

The station also hosts live-to-airs from various Toronto-area nightclubs three to five nights per week. Wednesdays have been wayback playbacks from Club Menage since 2002 (hence the term Wayback Wednesdays), but they have recently moved to Gravity Soundbar, Bloke, and now Ristorante Buonanotte. Thursdays are live from Sugar Daddy's in Mississauga, playing the best R&B, Hip-Hop, Reggae, and Dancehall. Fridays they broadcast out of Gravity Soundbar. Saturday nights are live from My Apartment in Mississauga.

On November 11, 2015, Tony Monaco announced that after nearly 14 years, Wayback Wednesdays would end on November 25, 2015.[7]

On March 23, 2016, Wayback Wednesdays returned to Z103.5, back by popular demand, broadcasting live from Ristorante Buonanotte.[8]

• Official website
• CIDC-FM history – Canadian Communications Foundation
• Query the REC Canadian station database for CIDC-FM