Wedding jitters are rising Down Under as temperatures drop in Sydney's coldest summer in almost 50 years.

Sydney had its lowest December minimum for 16 years on Monday, with the morning temperature dropping to 11.8 degrees. It was the coldest first week in December since 1960.

The Sydney Morning Herald reports that Aussie brides-to-be have been calling the Bureau of Meteorology for weather forecasts spanning up to two months in advance as the unseasonably cold weather is felt in Australia.

David Barlow of the bureau told the Herald that the weather agency could not keep up with the long-range forecast demands from brides-to-be. He said the standard update spans only seven days and beyond that, weather forecasters could only issue "climate outlooks.''

The Herald spoke to Amy Bing, 23, who got married yesterday. She claimed she had become obsessed with forecasts, phoning weather agencies several times a day. Just when she thought the weather was fine for their wedding photos yesterday, the sky opened up for showers.

Event planners and wedding organizers are getting more business than usual as couples prepare an undercover location plan B in the event of sudden rain on their wedding day.

The Herald also spoke to Melanie Pye, an events assistant at the Royal Botanic Gardens. She said couples would book an event on the lawn and a ''plan B'' in the event of an unexpected summer rainfall.

Pye said 80 per cent of the gardens' undercover locations are booked out for weddings, meaning couples are shelling out more than twice the actual amount needed for an outdoor venue just to be safe in case of rain.

Meanwhile, meteorologists expect the unseasonably cold weather to continue until Friday - the result of southerly winds blowing up from Tasmania.