Vaisala - Changes in company's own shares

SHARE REPURCHASE 23.5.2012

Vaisala Corporation       ANNOUNCEMENT       23.5.2012
SHARE REPURCHASE  23.5.2012                           
In the Helsinki Stock Exchange                        
Trade date                       23.5.2012            
Bourse trade              Buy                         
Share                     VAIAS                       
Amount                                 299  Shares    
Total cost                        4.574,70  EUR       
Average price/ share               15,3000  EUR       
Highest price/ share                 15,30  EUR       
Lowest price/ share                  15,30  EUR       
Vaisala Corporation now holds a total of 17.299 shares
including the shares repurchased on 23.5.2012.        
On behalf of Vaisala Corporation                      
Nordea Bank Finland Plc                               
Petri Simberg             Julius Summanen