During his school and university holidays he worked for various weather services.
He studied geography, mathematics and physics at the University of Zurich, where meteorology was not offered. He dropped out of the university before being awarded his degree and became a freelance contributor to a Swiss newspaper, the Sonntagsblick. In between he also worked for Schaffhausen local radio station Radio Munot. From there he moved to the Scientific Editorship of Swiss Television SRG and in 1988 he became Deputy Editor in Chief of Schweizer Illustrierte.
For a long time he had faxed unsolicited weather forecasts to Südwestfunk. Eventually these were adopted. In 1989, Jörg Kachelmann bought an old farmhouse in Bächli and rebuilt this into a high tech weather station. In 1991 he founded the Meteomedia AG weather service operating over 1000 weather stations in Germany alone.
In 1996 Kachelmann became Programme Director of the German version of the American television Weather Channel named Der Wetterkanal. After barely two years, however, the station discontinued the service citing "lack of viewer interest."
Apart from producing weather forecasts for ARD and various other broadcasters, Kachelmann acted in other areas. In 1996 he presented the German programme "Vorsicht Blöff", appeared from 1999 to 2004 on the MDR Fernsehen talk show "Riverboat", to which he returned in 2007 and which he gave up due to lack of time in 2009. 1998 he presented three shows of the quiz show "Einer wird gewinnen".
In April 2002 ARD changed its weather service provider from the German Weather Service, DWD, to Meteomedia AG. Since then he has presented the weather alternating with Claudia Kleinert, Sven Plöger and Alexander Lehmann, which airs before Tagesschau at 8:00 pm. Kachelmann has become famous for his unconventional presentation of the weather. A common fallacy is that he introduced words such "Blumenkohlwolken" ("Cauliflower clouds" for Cumulus) and "schlürfende Winde" (slurping wind). He denied this in an interview with the German newspaper Der Tagesspiegel. In January 2009 he became an Internet phenomenon after a cat joined him on set while he was presenting the weather.
The headquarters of the Swiss Meteomedia AG is located in Gais AR near to St. Gallen while the headquarters of German Meteomedia GmbH is in Bochum. In 2004 Meteomedia founded the Weather Information on Demand (WIND) system in Austria. He has been criticised for his commercial exploitation of the media and describing himself as a "meteorologist" without holding a recognised qualification. Kachelmann has also been criticised for his sensationalism. He established a weather station at the Funtensee in Germany because of the extremely low temperatures in winter (up to -45 °C) caused by the location of the lake. It is situated in a valley which is shaded by high mountains, forming a sink for cold air. Local hotel owners in the winter sport resort Berchtesgaden near the Funtensee are afraid that tourists stay away because of the reported low temperatures.
In March 2010, Kachelmann was arrested at Frankfurt airport in Germany after an ex-girlfriend accused him of raping her  following an argument in the previous month. After a trial lasting almost nine months, Kachelmann was acquitted on May 31, 2011. He theorized that his then girlfriend had invented the crime in order to destroy his life and complained about the intense media coverage of the trial, which he considered to be unbalanced. In a 2012 interview, Kachelmann claimed that concerning rape accusations, women would generally be regarded as victims, coining the term victim's subscription (German: Opfer-Abo). Subsequently, a jury of language scholars chose "Opfer-Abo" as the German Un-Word of the Year, thus criticizing its usage as inappropriate and inhuman. On 30 September 2015, a German court ruled that the Axel Springer publishing group and one of its subsidiaries have to pay Kachelmann €635,000 in compensation for the negative media coverage in its newspapers and online news services, especially German tabloid Bild, the highest such ruling ever in German judicial history.
- moneyhouse.ch: commercial register
- "Tatort Riverboat". MDR (in German). 1 January 2007. Retrieved 26 March 2010.
- ""Riverboat": Neue Crew ab März". MDR (in German). 30 January 2009. Archived from the original on April 15, 2010. Retrieved 26 March 2010.
- "Jörg Kachelmann: Ein Leben zwischen Hochs und Tiefs". brigitte (in German). Retrieved 26 March 2010.
- "Das Klima ist verrückter als das Wetter". Der Tagesspiegel (in German). 8 April 2004. Retrieved 26 March 2010.
- "Cat turns up on weatherman's set". BBC News. 9 January 2009. Retrieved 9 January 2009.
- Hall, Allan (9 January 2009). "Weatherman interrupted by cat during forecast". The Telegraph. Retrieved 10 January 2009.
- "Deutschlands Kältepol - Warum ist es so eisig am Funtensee?". Focus (in German). 24 January 2006. Retrieved 25 March 2009.
- "Berchtesgaden wehrt sich - Funtensee als Kälteloch fürs Winterloch". Bayerischer Rundfunk (in German). 14 January 2009. Retrieved 25 March 2010.[dead link]
- Levitz, David (29 July 2010). "TV weatherman Kachelmann released from pre-trial custody". Deutsche Welle. Retrieved 29 July 2010.
- "Weatherman Kachelmann arrested for alleged rape". The Local. 22 March 2010. Retrieved 25 March 2009.
- Joanna Impey (31 May 2011). "Weatherman acquitted of rape in 'trial of the year'". Deutsche Welle. Retrieved 31 May 2011.
- The Local: Victim subscription worst phrase of 2012. Published online on 15 January 2013
- "Rekord-Schmerzensgeld: Springer muss Kachelmann mit 635.000 Euro entschädigen" (in German). Der Spiegel. 30 September 2015. Retrieved 12 October 2015.