Why do tourists miss aurora ?  
 * Check the sky only once an hour
   or Check the sky after the aurora is over 
 * Check the sky in turn with friends.
   = The friend tells you "It WAS beautiful !!"
 * Check only half of the sky 
 * It is cloudy does not mean it will be cloudy 
 * Check the sky under street-lights
 * Go back before the eye is tuned to darkness
 * Mistake weak aurora as cloud
   !!! Use digital camera to monitor the color !!!
 * Found weak one, but too cold to wait break up
   !!! Wear warm & walk around to keep warm !!!
 * Yes, there was no aurora (very rare if not cloudy)