Vaisala Corporation ANNOUNCEMENT 4.6.2012 SHARE REPURCHASE 4.6.2012 In the Helsinki Stock Exchange Trade date 4.6.2012 Bourse trade Buy Share VAIAS Amount 125 Shares Total cost 1.850,70 EUR Average price/ share 14.8056 EUR Highest price/ share 14,85 EUR Lowest price/ share 14,70 EUR Vaisala Corporation now holds a total of 153.774 shares including the shares repurchased on 4.6.2012. On behalf of Vaisala Corporation Nordea Bank Finland Plc Petri Simberg Julius Summanen