The best tourist seasons in Shanghai are spring and autumn (March to May and September to November). Spring is mild (10-20°C) with frequent rain—pack a light jacket and umbrella. Autumn is cool (15-25°C) with significant day-night temperature differences; long-sleeved shirts plus a lightweight jacket are ideal. Summers are hot and humid, winters cold and damp—prepare for heat/cold during off-peak seasons. For customized itinerary planning or real-time weather alerts, contact service@intotravelchina.com for practical travel advice.