Cruise IAS/TAS/GS lower for warmer temps?

[LSaupe]

I am seeing about 5-7 MPH slower cruise (for a given RPM) currently in warm weather than during cold weather (70F vs 30F). I have 2 independent IAS and 1 GPS instruments and the are all trending the same way.

Is this common/typical/anticipated? I anticipated a bit of change due to density altitude, but only envisioned a TAS vs IAS change (which hasn't really changed much).

I took a 4 month break so went from one extreme to the other, so it is quite apparent. 582 Rotax, 3 blade GSC, Model III. No changes to aircraft (other than needle position change)

[Av8r3400]

In my area the summer brings thermals and rougher air which do impact performance, definitely.