Ytukyg

I started recently to bike to work, where we have a shower and I can change clothes. However recently I also started attending an evening course, where there is no place to change.

So when I commute to work, it's easy. At home I wear my warm cycling clothes and then at work I switch to light comfort ones.

However the problem happens when I want to go to the evening course. Since it's pretty warm at the classroom then I can't wear my warm cycling clothes and go to the course and stay with them for 2 hours. And since there is no place to change, then I can't change there to be able to return home from the course.

Any ideas on how to solve this? or any clothing alternatives/ideas?

My commute is pretty long. From the course to home is about 18KM.

Edit: the temperature in winter here gets easily below 0, and the worst is -18 to -20.

I've had success wearing legwarmers under trousers during winter.

The main advantage is at the far end you can either wiggle them down while standing, or drop your pants in the toilet cubicle and shove them down around your ankles for comfort.

This works well with overshoes, in combination with a decent jacket and gloves. I also wear a neck buff and/or helmet liner.

Try sitting nearer the window or door if you need a cooler breeze.

If you can't change in the toilets, you should complain about the disgusting state they're in. In the mean time, it's possible to change while standing on your shoes, if you're careful.

However, I would say that 18km isn't a very long ride – presumably not much more than an hour, probably less (though I don't know how -20 affects this). I don't find that I need padded shorts for anything less than around two hours, and I think you'd be fine without them, too. In that case, you can probably wear non-padded shorts "as underwear" and suitable layers, and you won't need anywhere private to change.

Make sure you get a good set of mudguards fitted as these really do make a difference to whether you get covered in grime or not. I've considered a cycling poncho for the wettest weather but have not bought one yet.

If you really need padded shorts (and I didn't for a 15 km commute, see the recent question on jeans in Amsterdam) wear them under your normal clothes for the evening journey. They aren't too warm in themselves, and you can get them designed to be underwear if you really want. I have even worn padded tights under jeans for a whole day in work. That was too warm even though the office was cool, but not much too warm.

For warmth, rely on overtrousers, that you can put on and take off without getting fully changed. Merely waterproof ones keep the wind off but at those temperatures you might be better off with fleece-lined ones. I assume you're in winter boots, so you might want to look into overtrousers that unzip a long way up to go on over boots. Your top half is simpler, as most people will be adding layers before going out into that sort of weather.

Bathroom stalls. Just learn to balance on one leg.

I've had success over the years finding shower/lockers in adjacent buildings if my employer's location was lacking. 1/2 the time they're semi-public so it's easy, sometimes I was able to convince building management to cut me some slack if they're familiar with my own building's shortcomings.

Also, don't rule out a local gym. I have an annual membership at 24 hour fitness and use the gyms for changing and showers before/after rides to work. You can even get around that 24-hour don't leave your stuff in the lockers rule by simply moving your clothes from one locker to the next each morning. Essentially, I bring a change of clothes for the day, leave my cycling stuff in the gym locker, shower...go to work, hit the gym to change back into my cycling gear and then head home. There are no lockers, showers or changing rooms at work so the gym is my "facility". I can also do some light workouts at the gym to break-up my AM/PM routine. Worth the $99/year...yes, I got a sweet deal with 24Hour when they were on the ropes ~10 years ago.

I think in your situation, I would recommend breathable outerwear over wool (or other less smell producing) undergarments.

Finding a setup where you have an easily removable outer layer (that is conducive to cycling in your chosen temperatures) over an underlayer that is presentable (enough) for a class shouldn't be that hard. Jackets/pull overs are easy enough and many companies make zip off style pants that can be easily removed. I recommend aiming for presentable for public and letting fashionable go. You might carry an extra pair of lightweight footwear to replace whatever is keeping your feet warm while riding.

Likely the more difficult problem is usually smell. Many performance sports garments will begin to smell after repeated use. Wool has a serious advantage here, while some companies also make synthetic garments with chemical additions to reduce the problem (with varying levels of success). Depending on how often your class is (I'd assume multiple times a week), washing garments every night might be impractical. I used to get a week or so out of my wool underlayers while commuting before they got too stiff to continue comfortably in. I would recommend multiple sets of cycling shorts (chamois shorts) so that they can be changed daily. Perineum health is not to be trifled with.

Try to find a local gym nearby your evening courses and if it's cheap, you can take all of its advantages. I mean shower and locker rooms.
The second advice is to find some windproof clothes that are easy to change. I know there are some examples in the market. I've even accepted a windproof jacket as a gift when bought a cooler.
Good luck, mate!