If this is the kind of consistency required to become world champions, a team such as Australia may be in a spot of bother. The Wallabies won six games straight in England in 2015 before succumbing to the All Blacks in the final but since then they have not known the meaning of the word consistency. The most wins they have strung together was four straight against Argentina, the All Blacks, Japan and Wales in 2017, while they won three in a row against Wales, Scotland and France in 2016.Last year, their worst since 1958, the Wallabies did not manage to win even two consecutive Tests, although they have this year with back-to-back wins against Argentina and the All Blacks in the shortened Rugby Championship.Every team with aspirations to win the World Cup in Japan will enter the tournament with the objective of remaining undefeated because history tells us that is what you need to do, but the 2019 tournament may well be the first to witness a team lose a pool game and come back to lift the Webb Ellis Cup.It has almost happened before. Twice teams have lost pool games – England to the All Blacks in 1991 and to South Africa in 2007 and France to the All Blacks and Tonga in 2011 – and still reached the final, while the French drew with Scotland in 1987 and made the decider.This World Cup is widely expected to be the most open ever. New Zealand are the favourites as always, but Ireland, Wales, England and South Africa are all genuine contenders, while the Wallabies, Argentina and France are dark horses.Certainly, all of the leading teams will be aiming to finish on top of their pools to earn, theoretically at least, a more favourable passage through the knockout stage, but the very evenness of the competition throws up the real possibility of a team losing a pool game and still managing to win the tournament for the very first time.There is no guarantee that Ireland, New Zealand, England and Wales will win their pools, and would anyone really be shocked if South Africa, France, Argentina, Scotland or Australia finished second in their pool, but went on to win the World Cup? Apart from being the most even World Cup in history, the 2019 tournament may also see a seismic shift in the balance of power between the northern and southern hemispheres.The three southern hemisphere superpowers Australia (two), New Zealand (three) and South Africa (two) have won seven of the first eight World Cups between them. The sole northern victor was England in 2003. But in this tournament Ireland, Wales and England are expected to have as much chance of winning as the southern heavyweights, while France always pull themselves together for the World Cup.The biggest threat to northern hemisphere success at this World Cup may be the unfamiliar hot and humid weather, which will be different to anything experienced in previous tournaments, usually played in mildness of a European autumn or Antipodean spring.The Japanese weather will be an advantage to the southern nations whose players are used to playing Super Rugby in the heat and humidity of February and March – at least at the beginning of the tournament. It would be wise to look at the long-term weather forecasts. After Japan’s typhoon season peaks in September the weather is hot and humid with temperatures around 23 to 28C, but drop to 19 to 23C in October. The final in Tokyo on 2 November could be played in a cool, crisp 14C to 18C.Most teams have prepared to play in hot and humid conditions, but that weather may only last for the first week of the tournament before cooler temperatures set in. Teams will need to adjust to changing weather conditions over the course of the tournament; tactics employed in sultry September may not work in the cooler climes of October and November.The Springboks, who play the All Blacks in a blockbuster Pool B game on Saturday night, have already flagged that they intend to play without the ball in the slippery conditions, but they may not want to play that way if they met Ireland or Scotland in milder conditions in the quarter-final. Australia rugby union team Support The Guardian Read more Share on LinkedIn Rugby World Cup Share on Messenger Share via Email Share on WhatsApp … we have a small favour to ask. More people are reading and supporting The Guardian’s independent, investigative journalism than ever before. And unlike many new organisations, we have chosen an approach that allows us to keep our journalism accessible to all, regardless of where they live or what they can afford. But we need your ongoing support to keep working as we do.The Guardian will engage with the most critical issues of our time – from the escalating climate catastrophe to widespread inequality to the influence of big tech on our lives. At a time when factual information is a necessity, we believe that each of us, around the world, deserves access to accurate reporting with integrity at its heart.Our editorial independence means we set our own agenda and voice our own opinions. Guardian journalism is free from commercial and political bias and not influenced by billionaire owners or shareholders. This means we can give a voice to those less heard, explore where others turn away, and rigorously challenge those in power.We need your support to keep delivering quality journalism, to maintain our openness and to protect our precious independence. Every reader contribution, big or small, is so valuable. Support The Guardian from as little as $1 – and it only takes a minute. Thank you. Since you’re here… Read more Wallabies go with Pocock-Hooper combination for World Cup opener Rugby World Cup 2019: Australia team guide James Horwill: ‘If the Wallabies turn up, they can beat anyone’ features Australia sport Reuse this content Rugby union Rugby World Cup 2019 Share on Facebook Read more Share on Twitter And how will the Wallabies cope with the change in the weather? The Australians seem intent on playing with the ball in hand, which could be tricky in hot and humid conditions against Fiji and Wales in their first two Pool D games. The Fijians are used to playing in hot and humid conditions and will become highly dangerous if the game becomes loose and unstructured, while Wales will probably give the ball back to the Wallabies and try to force mistakes.But in this most unpredictable of tournaments it may not matter in the end if a team drops a pool game. Depending on other results, it could even turn out to be an advantage in the knockout stage. Consistency will still be important, but losing one of the opening four games may not mean the end of the World Cup. Share on Pinterest Topics The Rugby World Cup has always been a tournament that, above all else, demands consistency. In the previous eight editions, the teams that lifted the Webb Ellis Cup won all of their games – pool and knockout. In the first four World Cups the winning team won six games in a row; the last four tournaments the champion side won seven straight.