We'd crossed Kansas without getting a century in a day ride (I couldn't handle the heat, which cut short a couple likely days). So when we got to Rawlins, WY and had a day off, we thought we could make Lander in one day.
Up and riding out of Rawlins as the sun rose, it looked like it was going to be a beautiful day. Stopped at Muddy Gap for more water and snacks, and noticed we'd be going into a moderate headwind. No big deal, right? By the time we passed Split Rock, neither of us wanted to get off the road for a mile because of the time we'd lose as the wind was picking up. Stopping for lunch in Jeffrey City, we smiled at the bird feeders duck taped to the parking stanchions; but 45 minutes later when we came out of the diner, we weren't smiling any more because of the howling wind. Still, we decided to push on.
We had food, and water, but pushing into the headwind was tough. Really tough. At one point I got curious: I was about 20 yards in front of my daughter, hopped off the bike and started walking. 15 minutes later she was 100 yards in front of me. OK, walking wasn't really faster.
It took us five hours to make 20 miles, including hitting 6 mph going down the last hill (probably 6% downhill) to the Sweetwater River. We were exhausted. No camping signs at the state rest area, so in desperation we went across the road and begged to be allowed to camp at the LDS facility. The staff offered us a place to camp, warned us to clean up after ourselves, and let us into the bathhouse. Bless them! After our supper, I went to talk to one of the hosts, and asked him what he thought the wind had been. He'd been pulling a trailer of pushcarts back from South Pass for a summer program, and said it was miserable -- there was no wind cooling him off in his pickup at 50-55 mph. I've claimed that 50 mph as the headwind we fought for five hours based on his observation.