How can I choose my time of visit to avoid the crowds at the Paris Catacombs?

Question

This includes time of day, day of the week, month of the year, season, anything useful.

I went here once around noon on a weekday recently and it was a 90 minute line, which is crazy-- no other attraction in Paris has had any line at all for me so far. Since the whole line is just standing outside in the open sun, and it was 95 degreees F, I had to just leave.

When do the crowds subside?

Answer 1

It is normal to see long crowds there (even Google Street View shows the queue), but google suggests it is less busy Wednesday to Friday, either around opening time (ideally get there sometime before 10 a.m. or in the late evening, around 6 p.m. maybe, last entrance time is 7:30 p.m.)

Even better, the catacombs have their own statistics on best access time (measured as average waiting time, for 2015).

clearly the best time to visit is

off-season from October to April, outside of school holidays, between Wednesday and Friday in the afternoon from 3 to 7 p.m.

in summer you are basically always in for a long wait, so come prepared, e.g. with an umbrella for shade, water and good company or something to keep you busy during your 90+ minute wait.