LONDON (Reuters) - Scottish drinks maker AG Barr (BAG.L: Quote, Profile, Research) on Tuesday pinned hopes of sales growth of 4-5 percent this year on expectations that Britain's summer would be a more "average" one than last year, the wettest since 1912.

Chief Executive Roger White said sales in the first seven weeks of the year were 3 percent ahead of the same period last year and it is well positioned to ride out an uncertain economic outlook, but the weather, as always, would determine its fortunes.

"The competition is probably less important than the weather," White said in a telephone interview with Reuters. AG Barr makes Irn Bru and Tizer.

"This year we would assume a fairly average summer as last year was exceptional in terms of how wet it was. On a five-year run, soft drinks have grown 4-5 percent per annum and I think that's certainly achievable (this year), yes."

A 5 percent increase equates to 2008 turnover of 155 million pounds.

Last year, England and Wales experienced the wettest summer since 1912 while for the Britain overall, temperatures were the lowest since 1998, the Met Office said on its website.

The company reported a 27.4 percent increase in pretax profit to 20.8 million pounds ($41.33 million) as turnover increased 4.6 percent to 148.4 million pounds for the year ending 26th January.

It proposed a final dividend of 28.00 pence per share for a total dividend for the year of 39.00 pence per share -- 11.4 percent more than the previous year.

The shares were unchanged at 1163 pounds, valuing the company at 226 million pounds.

(Reporting by Hsu Chuang Khoo; Editing by Quentin Bryar)