The training schedule I'm following recommends times and heart rate ranges rather than specific mileage. Today's was for four hours at event pace, and terrain specific. The wind got strong enough to slow me down, especially late in the ride. I tried to focus on keeping my heart rate in zone 3, instead of trying to push the pace.
As to "terrain specific", there aren't any hills in my neighborhood. I did four or five "simulated hills" by shifting into a gear that felt hard, and working to ride at 100 rpm for 30 seconds. Next time I must aim for 60 seconds! I actually hit a peak speed of 22.60 mph, which is very fast for me (in fact, it's a new record), but I wasn't there for long.
There were some very threatening-looking clouds around, and I was glad that it didn't begin storming. We've already had enough rain for a while.