She seems to find solace in knowing exacly how long we have left until the next holiday. And, by her calculations, next week is going to be a slump.
It is not the bleakest, weariest or the snottiest week of the year (save that for January), but it has the distinct misfortune of falling somewhere after the end of the beginning, yet not quite the beginning of the end.
And it is unremarkable. We have had our half-term fun and, in some cases, sun (a week in North Africa is, I swear, the most effective, if not cheapest, winter term tonic around).
We have covered Halloween crafts and the annual bonfire night-themed party lesson. ("Remember? Remember? Yes Miss, you made us do this last year...") And next week there is coldness, darkness - and a bit of a stretch until we can start making plans for Christmas activities.
I'm sure that part of my blueness is down to the fact that I have officially put away my summer clothes. No more floaty skirts and Birkenstocks, which only require a pleasing five seconds to don.
Now is the season of woolly tights and buttons, those complicated items of attire that add a crude 10 minutes to the finely tuned pre-breakfast routine.
There is, of course, a simple cure to this slump-week blues and their associated wardrobe issues - the oldest one in the book. On Thursday school finishes at four. The shops in town stay open until 10pm.
Now that calculates as about six hours of blissful retail therapy. Suddenly the inconvenience of winter clothes is replaced by the thrilling thirst for new additions to the staffroom style collection. Well, it is all about reward, isn't it?
Louisa Leaman is a London teacher