Playing Vinyl in a Cold Room

IMO it's not temperature it's humidity.
If you'll track it down you'll see some electrostatic effects.
18,5 isn't the bad one but if condensation starts it can make a lot of side effects

The relative humidity is 44%.
It should be OK.

Any idea how to solve this issue?
Should I try to change my tonearm settings - to lower VTA or higher VTF?

What you're hearing is a natural consequence of cartridge construction. The cantilever pivots on a donut shaped ring of elastomer. Like all rubbery stuff it changes getting harder and softer with temperature. 

VTA and VTF will change the sound a bit and maybe even in a way you like. They should always be set by ear, regardless. So yes you should explore that, always.

The answer however will be to physically warm it up with a blow drier. First thing you do after turning the system on. Hold your hand near the cartridge and hold the blow drier where its warm but not too hot. Not a lot of thermal mass in a cartridge, so this should only take a minute. Since you're hearing the effects of the cold its a slam dunk you will hear the effects of the warming.

Playing records the mechanical action of the cantilever will eventually accomplish the same thing. Only most of the tiny amount of heat generated will be lost to warming the mass of the cartridge. Once the whole thing is heated up though it should last a good long time. Do it a few times you will get the hang of it.

This is something I've thought about before. Every night, even after warming everything up a good half hour or more, still it takes about a full side to really sing. Through trial and error its been narrowed down to the cartridge. I've often wondered if its just this heating action or electrical. You've just motivated me to find out. Tonight.

Thanks!

Place a 100w incandescent bulb above the table which will warm up the surrounding area. 

If you're going that way: below. Heat rises.

No mc I doubt it. The mass of the elastomer is very low. It will revert to room temp very quickly. Alex just put ear muffs on it:) 
You need to put a radiant heater in the basement or move the system. I keep our house pretty cold in the Winter. No higher than 66 degrees. I have never noticed a problem with any of my cartridges. So, you might also consider getting another cartridge saving the EMT for warm Summer days. 
With a heater near the turntable you risk forming a temperature gradient across the record. This is how warps are made. 

@millercarbon wrote 

If you're going that way: below. Heat rises

The plinth would act as an insulator, therefore, you are better off having the light bulb above the table so that the electromagnetic radiation has a direct line to cartridge.  

Alex
It sounds like the suspension has hardened somewhat and the slightly cooler temps are highlighting this.
I do not consider 65 to be cold at all and I regularly play records when the temp is a fair bit lower in my room, say high 50,s.
I do let the system warm up for an hour and have a heater.... Pointed at me..lol.

A small electric heater. Don't make more of it than necessary. From an old old old listener. In two weeks it won't matter. Something else will. Don't stress.

The mass of the elastomer is very low. It will revert to room temp very quickly. Alex just put ear muffs on it:)

Made me go and check. OP bought a nude. How inconsiderate. Oh well, it'll warm up all the faster.

My Koetsu has a nice big brick of a body around it. Think I'll give it a minute or so to get nice and warm. Then another few minutes for the heat to sink in through all that quality Japanese aluminum and whatnot. Then have a listen. So in other words same warmup as usual for everything else, only tonight for the first time physically heating the cartridge up. Gosh for the first time kinda wishing I had one of those trick temp readers. Oh well. New trademark: Go and touch. You will feel.

mc it is time to put that bottle of wine down.

I’d rather a bottle in front of me than a frontal lobotomy. 
I know, I know, there’s people sure I had both.

My basement space drops to 58F in winter. Silent heater under my butt and 100watt lamp over table. I don’t notice a difference between the cold and when it heats up in Summer. I don’t mind the chilly air. Feels healthier, less drying out of the mucosa.

TT thread....
Word "mucosa"...
Why I read every thread...

Get a small and inexpensive space heater and a thermometer to measure the surrounding temperature. After a bit of adjustment you should be able to elevate the temperature around the turntable. Let things warm up a bit before using the turntable. Also a good idea to get one that doesn't have a noisy fan. That should help cold weather concerns.

Buy two older large monoblocks tube or ss This will always keep your room warm.Avoid class D

18,5 degrees celsius is pretty warm I'd say. Shouldn’t be allowed to have warmer indoor temp. Save the world.

My thermostat is set at 18.5 C and it doesn't affect the sound in my systems.

yall, vinyl  should be at an abient temperature...in extreme situations, freezing is the worst///the hi-frequency information is frozen and your line contact styus will shave the twin peaks in said groove.

austin estereo

"consider this" rod serling....preheat your groove w/ a gooseneck led lamp.