This is completely subjective, and more than likely has something to do with the human senses adapting, but I've had the same experience with drives over the years. The motor/disc spin vibration and seek noises seem to be rough at first if a drive starts off in low ambient (+16...+18 °C in the old house), and then smooth out over the next 30-60 minutes.
The Maxtors of yore (talking first-generation FDB here) were especially bad at dealing with low temperatures, if memory serves - they would audibly clack and whirr until they warmed up. A similar effect could be perceived in the Seagates I owned at the time.
There is no doubt an optimum temperature for everything, but what that is for hard drives (and their components) is subject to debate. Manufacturers only tend to offer Operating and Non-operating temperatures, but AFAIK have not offered recommendations in drive specifications for optimum temperature. Makes sense, as then the drives won't have to comply with as strict a temperature range, and can appear more rugged or multi-purpose on paper.
Case: FD Define Mini
Parts: P8Z77-M Pro µATX, N650Ti-1GD5/OC, G.Skill 2x4/1600/CL9 DDR3U, Xonar DX, WD G 1 TB, m4 128 GB, RX-5300 PSU
Cooling: Noctua NH-U12P SE2 + Scythe SS PWM, 2x Noctua NF-P12
Extras: Eaton UPS, Dell 24" EIPS, Ducky TKL kb, SteelSeries m, Synology DS213j 3+3 TB RAID1
idle & load: CPU 32 °C & 44 °C @ 300/600 & 600/800 RPM, GPU 35-65 °C @ 1200-1650 RPM