The airline and operator said it was keeping tabs on "unusual adverse weather conditions" in a small number of European destinations.
It follows disruption to its Rhodes programme earlier in the summer owing to wildfires, as well as its Skiathos programme owing to Storm Daniel.
The Balearics were also hit by high winds and heavy rains late last month, with the conditions leading to a collision between P&O Cruises’ Britannia and an oil tanker.
Closer to home, Exeter airport reopened on Monday morning (18 September) following flash flooding.
"We are currently seeing unusual adverse weather conditions in a small number of destinations across Europe which we know is causing concern for some of our customers due to travel," said Tui in an operational update issued on its website.
"Please be assured we actively monitor weather conditions in all the destinations we visit to be sure it is safe for our customers and colleagues. Should there be any concerns about a destination then we will be in direct contact with customers with options for their holiday.
"This might be a change in travel date or the option to change their holiday to a different destination. Our priority is looking after our customers and ensuring they have a safe and happy holiday."
