THE sun has got its hat on and is coming out to play.

Indeed, the sun is not only going to shine, it will blaze down over the holiday weekend, Shanghai Meteorological Bureau said.

Temperatures will rocket to 29 degrees Celsius tomorrow, ushering in a heatwave for the three-day Labor Day holiday. On Sunday, the high could even reach 30 degrees. But there will still be huge temperature swings between day and night temperatures.

The hot weather will be broken up by showers on Monday evening, forecasters said, with Tuesday cooling down to 23 degrees.

Dormund shurb roses are expected to be in peak season at Chenshan Botanical Garden over the holiday period, and peony blossom will brighten up Shanghai Botanical Garden.

Meanwhile, for those who plan for a holiday getaway, Shanghai Road Administration Bureau warns of an expected 17 percent rise of traffic volume today, and a 12 percent rise over the following three days.

Elevated roads including Yan’an, North-South and the Inner Ring Road are likely to face more congestion today during the afternoon and evening, as will expressways such as G2, G15, G40, G50 and G60 that lead out of the city.

Tomorrow, the first day of the holiday, traffic peak hours on the expressways will run from 8am to noon, while the northern and western parts of the Middle Ring Road and the part of Yan’an Elevated Road that connects with Hongyu Elevated Road will also be very busy, the bureau forecast.

On Monday, heavy congestion is predicted from 2pm to 8pm, especially for the Yangtze River Tunnel and Bridge, Wuning Road overpass at the Middle Ring Road and Yan’an Elevated Road.

A marathon is being held on Sunday by the eastern end of Chongming Island next to the Yangtze River Tunnel and Bridge at the G40 Expressway, and motorists are asked to take note.

About 2.6 million cars are likely to pass through city checkpoints at its borders with neighboring provinces.

As in other years, all expressways in Shanghai as well as Donghai Bridge will be toll-free to cars with not more than seven seats from April 29 to May 1.

Shanghai police said most traffic accidents during the Labor Day holiday over the past three years took place in Songjiang and Minhang districts and Pudong, all popular destinations.

Driving under the influence of alcohol and not giving way to pedestrians and bike riders at crossroads were leading causes of traffic accidents during previous holiday periods, police said.