The Magnum, Carte d'or and Ben & Jerry's owner has admitted ice cream sales took a hit in spring and early summer this year due to the cooler weather.
Unilever, which also owns brands including Hellmans and Dove, said the previous two summers had started positively, but this year - particularly in May - the weather had been far too cool.
Chief financial officer Graeme Pitkethly said: "There were a number of swings and roundabouts. It seems ironic with record temperatures (today) but during the period it was quite negative with strong early summers before."
It comes as the business revealed that total sales in the six months to June 30 rose 3.2% to €26.1 billion with pre-tax profits up 0.6% to €4.4 billion.
Elsewhere, the company said it had a strong six months in emerging markets, but was weaker in more established areas.
Europe was particularly bad, with sales down 0.6% to €5.8 billion, but this was offset in Asia, where sales jumped 6.2% to €12.2 billion.
Mr Pitkethly said Western Europe - and France, the UK and Germany in particular - suffered the most, while Eastern Europe saw a strong performance, especially with a boost in detergents.
Germany was particularly troublesome, with the company revealing it had fallen out with a major German supermarket, which had dented business there. Bosses declined to name the retailer.
The company's best category was home care, where underlying sales grew 7.4%, with strong sales of Persil and Surf.
But the company struggled in its food and drinks division, with sales of tea coming in weakly, leading to a rise in revenues of just 1.3%.
Unilever said: "In tea, sales declined with volumes impacted by weak consumer demand in developed markets. This was partially offset by black tea in emerging markets and our fruit, herbal and green tea ranges, including Pukka's premium herbal offering."
And in the US, the company revealed there had been difficulties in the condiment market, with heavy discounting of sauces hitting margins.
The company said: "Growth in our markets was mixed. Market growth in Europe and North America was held back by the impact of weather on ice cream sales. In the emerging markets we continued to see good momentum particularly in China and South East Asia.
"India saw strong market growth, though it moderated, as expected. Argentina remains hyperinflationary and high levels of pricing continue to weigh on consumer demand."