The best time to travel to Suzhou is April to October, when the trees and flowers of this garden city are green and in full bloom. Nevertheless, Suzhou is an excellent destination throughout the year as winters are mild. Suzhou climate is considered subtropical with an average temperature of 15 to 17 degrees centigrade. The annual average rainfall is 1076 mm. 
 
Suzhou is located in a subtropical monsoon zone, so the weather is mild and moist with four distinct seasons. It's best to visit Suzhou between January and April because the temperature is not too low and the flowers are in full bloom until June. The Plum Rain Season of June is followed by a hot July. After July, a harvest autumn arrives. Both the fresh fruits and the seafood will surely whet your appetite. To promote tourism in Suzhou, a number of tourist festivals are held here every year:

West Hill Plum Blossom Festival in Wu County - March, 1st to 10th
The Tiger Hill Flower Festival - March to May
Luzhi Apparel Cultural Tourist Festival - April
The Tiger Hill Fair - September to October
Tianping Hill red Maple art Festival - November
The Festival of Listening to the Bell of the Cold Mountain Temple on New Year's Eve - December, 31st

Detailed information about the Average, Maximun and Minimum Temperatures and the rainfall in Suzhou.

Average Data	Jan	Feb	Mar	Apr	May	June
Average High (F)	45/48	46/50	54/58	65/68	74/78	80/84
Average High (C)	7/9	8/10	12/14	18/20	23/25	27/29
Average Low (F)	31/34	33/36	39/43	49/52	58/62	66/70
Average Low (C)	-1/1	0/2	4/6	9/11	14/16	19/21
Rain (in)	1.6/1.7	2.4/2.5	3.3/3.4	3.9/4.0	4.2/4.3	6.3/6.4
Rain (mm)	40/45	60/65	80/85	100/105	105/110	160/165

Average Data	July	Aug	Sep	Oct	Nov	Dec
Average High (F)	88/92	88/92	81/84	72/76	61/65	50/54
Average High (C)	31/33	31/33	27/29	22/24	16/18	10/12
Average Low (F)	74/78	74/78	67/70	56/60	46/49	35/39
Average Low (C)	23/25	23/25	19/21	13/15	8/10	2/4
Rain (in)	5.1/5.2	5.0/5.1	5.1/5.2	2.2/2.3	1.8/1.9	1.4/1.5
Rain (mm)	130/135	125/130	130/135	55/60	45/50	35/40