Vaisala Corporation Stock Exchange Release December 22, 2010 at 12.00 Vaisala Oyj's 4000 unlisted shares (series K) have been converted into listed shares (series A). The conversion has been registered in the Finnish Trade Register December 22, 2010. Listing of the new series A shares has been applied for as of December 23, 2010. Further information: Jouni Lintunen, CFO, +358 40 5790181 Vaisala Corporation Distribution: NASDAQ OMX Helsinki Oyj [HUG#1474182]