AS summer turns to autumn and the nights begin to draw in the change of season can trigger the onset of winter blues, leaving sufferers depressed and irritable.

According to new figures from Scotland's largest council the phenomenon may also be having an impact on the number of pupils suspended from school.

A report on trends in exclusion by Glasgow City Council shows many happen in November, with more than 300 incidents compared to fewer than 200 in September.

The analysis also shows another spike in suspensions and expulsions towards the end of March.

Officials have now asked school staff to look at the two periods of increased exclusions to see whether different approaches can be taken to reduce the numbers.

Maureen McKenna, the ­council's director of education, said: "We wanted to have a look at exclusions across the year to see the peaks and troughs and it was clear in both the primary and secondary figures that there were two definite spikes. Both these higher points come towards the end of terms and it may be that school stress levels get a bit higher at these points.

"It may also be the onset of the darker nights in November with the weather changing may also make people a little less tolerant."

A spokesman for the ­Educational Institute of Scotland teaching union said it was not unexpected the number of exclusions may rise toward the end of a school term.

He said: "Some pupils can feel more tired later in the year, with the result that class indiscipline may increase. In addition, schools will often issue several warnings for indiscipline to a pupil before resorting to exclusion which means that, later in the term, repeatedly disruptive pupils may have used up all their warnings.

"While no-one wants to see pupils excluded from school, it remains an essential part of school discipline policies which is used as a last resort to discourage repeated or serious pupil indiscipline."

Total numbers of ­exclusions are continuing to decrease in Glasgow with a 10% reduction in incidents across all sectors.

There has been a further 15% reduction in the number of half-days lost to exclusion from 2011/12 to 2012/13 with numbers dropping from 2854 to 2574. The numbers are also significantly down from the 7500 cases in 2006/07.

However, there has been an increase in the number of more serious incidents - from 134 to 141.

Stephen Curran, the council's executive member for education, welcomed the decrease. He said: "With increased attendance, reductions in exclusions and attainment across the board at an all-time high, Glasgow is constantly driving up standards in education and we are really starting to see the benefits.

"If our children are not in school then they are not learning. Parents can be assured we will build on this success story and continue to raise standards across the city."

Under the policy of reducing exclusions, schools first put in place support for disruptive youngsters, rather than applying for exclusion.