[techcode]

Big companies mostly work on quarterly (so earnings call) cycle.

Hence depending on general economic situation (and of course specific industry/company). And just like you might be getting sweet offers to change your insurance/ISP/etc, recruiters/head-hunters might be encouraged to hit their KPIs a bit higher the closer to end of quarter/half-year/new years it is.

Also bigger companies might reorg (both teams/people and change plans/KPIs which is usually known as pivot) around new years - for those same reasons.

With all of that - January/February is usually "Let's see how the latest course of course adjustment is going to play out".