This is an anectdotal experience- i mixed two brands of liquid handwash soap without adding any water, and the mixture surprisingly appears less viscous (I have not measured with any device, but can tell from ease of flow) in winter months compared to standard handwash soaps I experienced in summer. can you tell why?

The handwashes are not alcohol or glycerine based- these are soap based. I know sodium stearate, palmeate, oleate etc. are main components of body washing solid soaps. Using potassium instead of sodium makes the soaps softer. and the liquid soaps are sodium laureth or pareth sulfate (or sulfonate?) based. This is not like deteregent where cationic and anoic detergent mixed together produces a buch of much-less water soluble entangled polymers. Even If I assume (polymeric) ionic liquid formation scope, even then viscosity reducing with temperature does not make any sense. Or does it? I know thermoplastics show higher elastic modulus at higher temperature sometimes due to entropic effect. Is something like that happening here? can you tell me whether there ane widely circulated liquid-soap-based handwashes that are not laureth or pareth based? Or what can be the role played by additives into the handwash?