Noticed also couple of days ago.
Link to news (in Finnish)
http://www.ts.fi/uutiset/kotimaa/574...an+kuukaudeksi
Very wise decision to make it in July, majority of business travellers are on their holiday as I think most of traffic for TKU comes from regional shuttles for connecting in HEL, ARN or CPH and hardly ever these are priced competetively compared to departure ex-HEL for leisure travellers. As said in link, TNT will also have to change their cargo planes to and from TLL to HEL for July.