Cycling Average Speed

OP that's good progress. I started in the spring and first ride was 14.5 mph over 12 miles on a flat course. Now regularly ride over 20mph when in a group over 30 miles rolling course and can average 19 over a century on similar terrain solo.

Think the level of improvement depends on your starting base and the frequency/determination with which you ride. Having a goal certainly helps. Mine was to be able to ride a century by the end of the summer. My first was a flat course at steady 15mph to make sure I made it. Once you know the endurance is there you feel more able to press on.

My plan for winter motivation is riding Velothon Wales next year. I want to climb the tumble in around 23 minutes.

As others have said, speed comparison alone doesn't meam much. Those living in a hilly and/or windy area will generally have a lower average. As you are asking about improvement over time however, I guess the question is still valid.

I am 58, and have been cycling on a "proper" road bike for about 2 years now.  My first rides were 12 miles at an average of about 12mph. 3 months in I was doing 20 miles at 15mph. At the end of year one, a typical ride was 30 miles with 1500ft total climb at 16mph average. Now I'll do that sort of ride at around 17.5mph, and at my age I don't expect to get much faster. Endurance has improved a lot, and 80 miles with 4500ft of climb is doable at somewhere between 16 and 17mph.

Despite the python's "strava w..." comment, if you are on Strava, it does form a good way of comparing your speed with others on the same routes you ride, and measuring your own improvement. Just don't get too hung up on the KoM thing - on one local 1.4 mile segment, the guy who holds KoM did it on a 4 mile total ride, with a tailwind, so it means SFA. But if you are cycling to improve or maintain your fitness, it useful to have some way to measure progress.

Incidentally, I noticed my times dropping over the past couple of weeks, which just happens to coincide with ambient temperatures falling by about 10degC, so I did a bit of research. Increased air density, increased tyre rolling resistance, and the impact of wind chill on the body all conspire to slow us down at this time of year.

I try not to get bogged down in averages, everywhere I point my bike is a hill in Cornwall. Having said that, 50 miles 4000ft climbing on my own I can knock out at 19-20mph. Our local tt is a sporting 10 I have only done it once and that was 24.24 on a road bike. I have raced one 25 TTT that averaged over 27mph, again on a road bike but I was mostly making up the numbers in that one!

2.5 years ago I was doing maybe 15/16mph on a 30mile ride. Now I can do a 2,000m century in under 4 hours 50 minutes (solo), which is pushing 21mph. Once I get my deep carbon wheels on, that'll increase to over 21mph I'd imagine.

If I'm TTing I can push 25mph on a, relatively hilly, 25 mile (not a TT bike, mind you).

That's a good gain in 3 months though - just keep pushing yourself harder.

Starting off; about 8-9mph. On my commute usually around 15mph, depending on how much stop/start there is. In a group fairly comfortable bimbling along at around 16-17mph.

Really depends on terrain and type of bike you were riding,  My early speeds if I remember were 13/14mph on a mtb bike, 16/17mph once on a road bike.  I can ride at 20+mph on the flat in a group.  Dont get hung up on averages, train hard and ride as often as you can and speed will rise.  I tend to think  of it differently, like how easy was it to stay in the pack on a club ride.  These days its a little easier, than for the first year or so.

Think I was the same when I started 3 and a bit years ago. Now when I'm on my own I tend to average between 16.5 and 17 mph over 20 to 30 miles and 18+ mph over 50+ miles when I am motivated by being in a huge group on a charity ride.