Music and tennis fans will be watching the weather forecasts closely over the coming days as two great events, both highly weather dependent, take place in the UK.

The Wimbledon Championships in London remain one of the highlights of the tennis calendar. Of the four major tournaments, the others being the US, French and Australian, Wimbledon is the only one still played on grass, a playing surface susceptible to the effects of heavy rain.

Despite the introduction of a retractable roof over the Centre Court in 2009, the early stages of the tournament are particularly vulnerable to the vagaries of the weather. With so many matches scheduled in the first week, prolonged rainfall can result in significant fixture congestion.

The middle Sunday of the two week tournament, traditionally a rest day, has been pressed into service during years of particularly wet weather. This was the case in 1991, 1997 and 2004.

The Glastonbury Music Festival is even more weather dependent. The Glastonbury Festival of Contemporary Performing Arts, to give it its full name, will be attended by 135,000 people.

Glastonbury is not a purpose-built venue, far from it. The festival takes place on a small dairy farm in the middle of the Somerset countryside in southwest England. Cattle are moved from the fields each year to make way for the likes of T.Rex, David Bowie, Paul McCartney, R.E.M., Muse and, this year, The Rolling Stones.

Even small amounts of rain can cause the fields to turn into a quagmire when so many people are walking to-and-fro all day. 1998 and 2005 were particularly bad years; the latter event being hit by a massive supercell storm which seemed to single out Worthy Farm for the very worst of the rainfall.

More recently, there have been improvements to the drainage and Glastonbury has seen somewhat better weather in the last few years, with 2010 being particularly warm and sunny.

The forecast for both Wimbledon and Glastonbury is generally favourable. Wimbledon is at risk of occasional light showers until Friday, but the weekend and early part of the second week are expected to remain mostly dry.

Down on the farm, it is expected to be dry for much of the Festival although mainly light rain is expected late on Thursday and through the first part of Friday. The weekend, however, will see the sunshine returning with temperatures into the low twenties Celsius.

Source: Al Jazeera