A return of the high summer temperatures affected a lot of films in the UK this weekend, but Columbia TriStar's Terminator 3: Rise Of The Machines rode the heatwave with a massive $9.8m (£6.1m) gross from 478 sites playing 762 prints.

The launch figures included Thursday previews of $1.7m (£1.05m) from 417 sites. Discounting the previews Terminator 3 was the fourth biggest three-day opening weekend of the year behind The Matrix Reloaded, X2: X-Men United and (narrowly) Bruce Almighty.

The success heralds a major comeback for Arnold Schwarzenegger in the UK. The launch gave the action star his biggest ever UK opening, with or without the previews included, ahead of Warner Bros' Batman & Robin which claimed $7.9m (£4.9m) from 457 sites in 1997 and Guild's Terminator 2: Judgement Day which grossed $7.5m (£4.7m) from 302 sites in 1991. Terminator 3's opening was 30% up on T2.

Moreover , with the exception of UIP's True Lies (1994) and Batman & Robin, Terminator 3's first four days gross was superior to the total gross of any Schwarzenegger film released since Terminator 2.

The results are particularly impressive considering the soaring temperatures; similar phenomena proved damaging to the opening weekends of Charlie's Angels: Full Throttle and The Hulk last month.

Terminator 2 was Schwarzenegger's highest grossing film in the UK with $29.2m (£18.2m). Terminator 3 will come under heavy competition next week, however, from BVI's Pirates Of The Caribbean: The Curse Of The Black Pearl.

T3 was not the only film successfully combating the weather. 20th Century Fox's Legally Blonde 2 (branded Bigger, Bolder, Blonder in the UK as opposed to the US's Red, White & Blonde) played the female counter-programming card well against Terminator 3 to take $2.5m (£1.5m) from 351 sites - including $466,638 (£290,249) if previews from 270 sites. The comedy landed second place behind the Schwarzenegger sequel.

The Reese Witherspoon sequel saw a 6% improvement over the 2001 original's opening. Legally Blonde went on to gross $9.7m (£6.1m) in the UK.

Third place went to BVI's Spy Kids 3-D: Game Over with $1.6m (£979,374 from 377 sites. Robert Rodriguez's third instalment in the children's franchise may have suffered the heat slightly, unable to match the openings of either the 2001 original, which claimed $1.8m (£1.1m) from 403 sites upon opening, or 2002's first sequel The Island Of Lost Dreams - $1.7m (£1.07m) from 409.

Spy Kids 3-D did hurt other kids' market titles, however, with Daddy Day Care dropping 67% this weekend; while Sinbad: Legend Of The Seven Seas and Agent Cody Banks were down 58% and 74% respectively in their second weekends on release.

The only other wide opener this week was BVI's Veronica Guerin which opened across the UK after playing three weeks in the Republic of Ireland. Despite success in Ireland, where it had grossed $2.7m (£1.7m) in its first three weeks on release, the film was unable to beat the heat and the competition in the UK.

This weekend it took $546,611 (£339,992) from 254 sites across the UK and Ireland, up just 35% from the previous week's Ireland-only gross despite adding 198 sites.