Summer trade exceeded expectations for less than half of about 250 tourism operators surveyed by the Tourism Industry Association (TIA) in March.
Almost 10% of operators said they had an excellent summer, while 37% said it was good, the association said on Wednesday.
However, 26% rated the summer season as only fair and a similar number rated it as poor or very poor.
The poor weather through much of New Zealand, especially in the North Island, affected many operators, particularly those providing outdoor activities.
Some operators said normal visitor patterns had been disrupted by last year's Rugby World Cup.
"There was a definite pattern of market displacement due to RWC 2011," association policy and research manager Simon Wallace said.
"TIA members are telling us that visitors from some of our key markets timed their trip to coincide with the tournament, so we didn't see the normal peak season pattern."
However, the association was confident New Zealand hosting the World Cup would provide long-term benefits for the tourism industry, outweighing any short-term disruptions, Mr Wallace said.
"It's clear from the survey results that the lack of a major event in 2012 is contributing to uncertainty among operators about what the next 12 months will bring."