BERLIN, May 25 - The weather in Germany could be as full of surprises as the soccer during the World Cup, with cold fronts, heatwaves, heavy rain, bright blue skies or severe thunderstorms among the myriad of possibilities.

Weather forecasters are loath to predict more than seven days ahead even though computers have improved the reliability of medium-range outlooks to 95 percent since the last World Cup held here in 1974.

Past June-July weather data is also a poor guide because the northern European country with both continental and maritime influences can have damp and chilly weather or hot and dry spells. Some years have maddening bouts of both in quick succession.

"You can't predict what will happen in June because there will always be surprises," said Gerhard Lux, a meteorologist at the Deutscher Wetterdienst (DWD), the national weather service.

"Everything is possible," he told Reuters. "It depends on many factors, especially on whether the prevailing winds are from the west, which are often wet and cool.

"Or they could be from the north, which are often cold, or southwesterly winds, which are moist and warm, or from the south, which are hot, or southeast, which are dry," Lux said.

Because heavy rain played a role in 1974, especially when the West Germany hosts beat Poland 1-0 in the "Wasserschlacht von Frankfurt" ("Water battle of Frankfurt"), the heavens will be on the minds of players, coaches, fans and bookmakers.

HAIL STORM

The historical data show a wide range. The June average is 15.4 degrees Celsius but a June average low record of 11.2 was set in 1923 and an average high of 19.4 in 2003. An all-time June low of 2.4 degrees below zero was recorded in Obertsdorf in 1962 and a high of 38.2 degrees was set in 1947 in Frankfurt.

A storm with tennis-ball-size hail hit Munich on July 12, 1984, injuring 300 people and causing a record 3 billion marks ($1.4 billion) in damages to cars and buildings. There have also been tornados and severe thunderstorms in June in recent years.

June weather can be unsettled but farmers and weather-watchers pay attention to some key dates.

The first is the so-called "Schafskaelte" -- or "sheep's cold spell" -- and temperatures sometimes drop by about 10 degrees to five to 10 degrees when it hits around June 9 -- the opening day of the finals this year.

The next critical date is June 27. According to German folklore, if it rains on this day, it will rain for the next seven weeks. But if it is sunny, statistics show the next few weeks are also warm and dry about 70 percent of the time.

Other meteorologists have examined the weather data since 1994 and predicted that the coldest match, at least based on past data, will be the Group E meeting between the Czech Republic and Italy in Hamburg on June 22 -- 14.8 degrees. The hottest will be June 21 in Frankfurt -- Netherlands v Argentina -- with 19.3 degrees, they say.

The driest date will be June 26 in Cologne, where it has rained only twice in the last 11 years on that date. The winners of Group G meet the runners-up from Group H then.

All quarter-final matches are on days at venues with a high probability of rain. The semi-finals may also be wet. Munich and Dortmund have had heavy rain on the relevant dates for the last 11 years.

HEAVY RAIN

Warm and dry weather may be preferable for some teams, fans, and journalists, but rain has often helped Germany teams -- as seen in their 1974 victory over a great Poland side.

Twenty years earlier, in 1954, outsiders West Germany came from two goals down to beat Hungary in the final in Switzerland -- played in heavy rain the Germans called "Fritz Walter weather" in honour of their captain who excelled on wet pitches.

Frank Boettcher is a meteorologist who has studied weather data and match results of the six past World Cup winners and found that Italy and Germany do well compared to Brazil, Argentina, England, and France when temperatures are extremely high.

"If temperatures are over 30 degrees or there is a strong thunderstorm with heavy rain, Germany would almost be on equal footing against Brazil," said Boettcher, who studied conditions for 93 matches of those top six teams for "Wetter Magazin".

He said Italy topped the list in hot weather over 27 degrees although Germany did nearly as well in the heat. The two were at the top of the statistics with the average temperature of their wins above 23 degrees. Brazil, by contrast, topped the six-team table when temperatures were below 18 degrees.

Germany fared worst of all in windy conditions.

"Higher temperatures help the outsiders," said Boettcher, theorising that passes may not be as accurate in extreme heat. "Teams with more talent sometimes struggle. But I have a feeling Brazil won't be bothered even if a thunderstorm hits the final."

Updated on Wednesday, May 24, 20