Winter is long as in most areas of Russia. Temperatures as low as -10 Co are normal, and - 20 Co is not unusual. The average winter temperature is -6.9 Co.

The Neva River freezes between November 25 and December 5 and the ice is gone only by mid-April.

Spring can be quite long. From early April temperatures are above freezing and by April 15 all the snow normally melts. One should be prepared for some chilly rainy days, but it can get rather warm mid-May onwards.

Summer vary from year to year, but generally temperatures are somewhere near +20-25 Co. You ought to have some clear days to enjoy the White Nights. Hot sunny days are not rare, but you never know when it is going to rain.

 July is the hottest month of the year. It usually starts getting a bit cooler in mid-August. The highest temperature ever recorded in the city was +33.6 Co.

Autumn (feel free to call it Falls) starts with reasonably warm days in mid-September, but by mid-October it is often chilly. The average September temperature is 10.8 Co, and the average October temperature is 4.9 Co . In November it might start to snow, but sometimes it does not snow until mid-December.

Clothes. What to bring.

Whatever the season, it is wise to bring your umbrella and a windproof raincoat or jacket. You will do a lot of walking in St. Petersburg, so think carefully about footwear. Depending on the time of year, you will need warm boots with a non-slip sole, waterproof boots/shoes, comfortable sandals.

In Winter it can get very cold outside, but hotels and homes are reasonably well heated, which makes it a good idea to dress in layers.
In Spring it might be chilly at times, but in mid-May it gets warmer. You can wear shorts in Summer, though shorts might prevent you from entering churches. Bring a sweater or light jacket for those chilly evenings.
It is in Autumn that you are most likely to use your umbrella and waterproof boots, though a Russian version of an Indian Summer (around mid-September) can be mild and fairly dry.

Longest Day. 17 hours, 31 minutes on June 21. The sun rises at 4:43 and sets at 22:20. 

Shortest Day. 6 hours and 57 minutes on December 22. The sun rises at 9 and sets at 15:57.