A recruiter would be a better point of reference here, but hiring season for interns is usually towards the end of the year. Experienced positions usually start heating up before bonus payouts and are probably at their peak around this time of year I think. This year is special, though, due to Corona virus with a lot of staff working from home etc.
On a renown jobsite, there are 12 internships, 313 entry level positions, 352 associate level available out of 906 results for a "quant phd" search worldwide.
When I checked last time last month there were much much fewer than that.
I should look this up every week and observe the ebb and flow.