Background/Aim: Early delivery (<39 gestational weeks), including early-term and preterm birth, is related to higher infant mortality and neonatal morbidity. Previous studies have shown that extreme temperatures increase the risk of early delivery, however the effect of unstable weather conditions remains unclear. This study aimed to investigate the association between temperature variability (TV) and early delivery in Shenzhen, China. Methods: We obtained records of 293,463 spontaneous early deliveries from Shenzhen Obstetric Data Reporting System during 2003-2012. Meteorological and air quality data were collected from meteorological bureau. TV during 6 exposure windows (preceding 2 days, 3 days, up to 7 days) , was separately calculated from the standard deviation of minimum and maximum temperatures (Yuming Guo, 2016). A time-stratified case-crossover analysis with conditional Poisson regression models was used to assess the relationship between TVs and early delivery, adjusting for mean temperature, humidity and air quality index. Results: TV ranged from 0 to 6 °C. The elevated TV0-1, TV0-2 and TV0-3 significantly increased the risk of overall early delivery, especially for preterm birth, and the effect of TV0-1 was the most obvious. Compared with the median of TV0-1 (0.5 °C), the relative risks for early delivery and preterm birth were 1.005 (95%CI: 1.000-1.011) and 1.019 (95%CI: 1.006-1.032) at 99th percentile of TV0-1 (2.74°C), respectively. TV0-1 effect was modified by delivery season, maternal education and parity. Low educated mothers, multiparae or those deliveried in spring and winter were more likely to delivery early due to TV. By stratified analyses, the TV0-1 increased the early delivery risk due to preterm labor, while the risk of early delivery following premature rupture of membrane declined. Conclusions: Temperature variability may trigger spontaneous early delivery due to preterm labor, especially during spring and winter. Pregnant women with lower education and multi-parity should pay more attention to unstable weather.