Just when it seemed like winter's grip on Toronto might never end, spring has finally sprung in the city and with it comes the start of the annual Cherry Blossom Festival.

The city expects thousands of visitors to descend on High Park over the next week and a half to take in the spectacle created when the buds of the Japanese sakura trees blossom into beautiful white and pink flowers.

And while it is notoriously difficult to predict the exact blooming date for the precarious trees, the High Park Nature Centre thinks some trees will start blooming this weekend.

According to the centre, the buds have entered stage three of growth, meaning the florets are extending out of the buds.

The centre predicts "peak bloom," when 70 per cent of the blossoms open, to occur between May 9 and 14. But the bloom period will last for only a week or two depending on the weather.

This photo from May 1, 2018 shows a cherry blossom in the third stage of growth when the florets start to extend out of the buds. (Steven Joniak/Sakura in High Park)

The Sakura trees in High Park were a gift from the Japanese ambassador to Canada, Toru Hagiwara, on behalf of the citizens of Tokyo. The trees were planted in appreciation on behalf of Toronto accepting re-located Japanese Canadians following the Second World War.

Steven Joniak, also known as Sakura Steve, is a cherry blossom enthusiast who runs the website "Sakura in High Park." He became interested in the Japanese sakura years ago and now follows their development every year.

"They're just a spectacle to see. They're so beautiful," said Joniak.

Joniak has been watching closely for signs of the bloom. In his latest video, he predicts peak bloom will take place between May 9 and 12.

The prolonged winter weather and out-of-season ice storm from two weeks ago delayed the blooming time, according to Joniak.

But since the weather turned last weekend bringing warmer temperatures this week, it's really helped push the trees to progress, he says.

The cherry blossom blooming period begins when 20% of the cherry blossoms are open and ends when the petals fall. (Steven Joniak/Sakura in High Park)

Joniak says he expects to see a mixture of blossoms and leaves this year.

"In previous years when the weather was more predictable the buds would normally go to blossom first," said Joniak.

"But in more recent years as the weather has been more temperamental, the buds from the leaves have been coming out at the same time as the blossom buds."

Thousands of visitors expected at High Park

The annual bloom means there will be increased pedestrian and vehicle traffic around the High Park.

"The spectacle of watching these beautiful blooms come out, that's more what people look forward to," said Joniak.

This weekend and next weekend are expected to be the busiest. The Cherry Blossom Festival takes place from May 4 to May 13 at High Park.

Toronto police say drivers can expect delays in the area and should consider alternate methods of transportation. The main streets surrounding High Park that will be affected are Bloor Street West, Keele Street. Parkside Avenue and Lake Shore Boulevard West.