Despite Judy's sarcastic denial, there's no question it's a regional issue, and a seasonal one too, for precisely the reasons Jcarr explained (the behavior of elastomers varies with temperature and humidity).
Years ago Raul paid us a visit, travelling from Mexico to CT, just so we could hear his then new preamp! I warmed the system up before he arrived and we played LPs all afternoon. Everything was sounding great.
We broke for a two hour dinner, then returned to playing more LPs. The sound was dull and lifeless, even though we'd left the electronics powered up. I should mention that it was the dead of Winter, fiercely cold outside (~0F) and bone dry air. Surmising that the cartridge suspension had cooled off and stiffened up (per Jcarr's explanation above) I tweaked VTF up by a hair, no more than a few thousandths of a gram.
Wham! The sound sprang to life again, instantly. Raul asked what I'd done and I showed him, alternating between "dead" VTF and "alive" VTF... a tiny adjustment.
The sweet spot for VTF in those conditions was incredibly small, but it was there. Just had to find it.