The analysis of data assimilated in the UK Met Office and NCEP models shows that there exists a sufficiently strong (in the range of about two months) interannual variability of the spring-time breakup date of stratospheric circulation. The preliminary results show also that spring-time transition depends on the planetary-wave activity in the stratosphere and during the last decades there is a tendency of the shift of the breakup to the later date. The main purpose of the present paper is to investigate the possible reasons of observed interannual variability of the spring-time breakup date. Increase of the amplitude of stationary planetary wave with zonal wave number 1 (SPW1) observed during the last decades in February leads to a substantial decrease of the SPW1 amplitude in March that can explain the observed shift to the later spring-time breakup date. Scatter plot between NAM and the spring-time breakup date shows a positive correlation, which is stronger for the early spring-time transition. Under east-QBO taken at 40-50 hPa according to the established classification, growth of the SPW1 amplitude is accompanied with the early spring-time transition. Under west-QBO conditions the correlation between the SPW1 amplitude and the date of spring-time transition is positive. Statistically significant positive correlation between MEI index of ENSO and spring-time breakup has been obtained under east-QBO conditions. This means that cold ENSO leads to early occurrence of spring-time transition in spite of the stronger polar vortex.