Good weather in northern Europe and the releases of the Lego Movie helped boost sales at theme park operator Merlin Entertainments.

Sales rose by 12% in the 18 weeks to May 3 over the same period last year.

However, the company cautioned that this period of outperformance should be seen in the context of a “suppressed performance” in the equivalent time in 2013 when results were adversely impacted by earlier Easter holidays and extremely cold weather in Northern Europe.

“As a consequence, underlying trading is consistent with the long-term growth trajectory of the business and full-year expectations remain unchanged,” the company said in a trading update yesterday.

CEO Nick Varney said: “The more favourable weather in Northern Europe together with strong promotional activity around ‘The Lego Movie’ launch for our North American Legoland attractions has meant a good start to the year.

“However the strong summer trading in 2013 will mean that like for like growth will be considerably more challenging over the coming quarters. As such, full year expectations remain unchanged with the group’s underlying trading being consistent with the long term trajectory.

“Overall, we anticipate further strong underlying growth across the Group, as we continue to execute on our six strategic growth drivers.”

Five openings are planned for this year: a Madame Tussauds and Dungeon in San Francisco; Madame Tussauds in Beijing and Singapore; and a Legoland Discovery Centre in Boston.

Three openings are planned for 2015 in Orlando, one in each of Istanbul and Michigan, and Shrek’s Far Far Away Adventure on London’s South Bank.

“The group continues to be actively engaged in searching for new brands and strategic opportunities that fit Merlin’s strict investment criteria,” the company said.