Hmmm...Mr. SuicidePace (Have you ever run a suicide pace?)
First off, you're in WAY over your head in terms of running experience, knowledge, and accomplishments compared to me. I don't even know you and I'll bet my last dollar I'm right. That's a fact, and please don't reply back claiming otherwise because I'll embarrass you. Second, "Best possible temperate"???? WTF????
Please note: "When it came to running marathon-like distances, 49.4 degrees Fahrenheit was found to be the ideal temperature for men, while 51.8 degrees Fahrenheit proved best for women. That being said, I'll back off my low 60's comment (better for 5k-15k), but the low 50's +/- is spot on. FYI- When Kipchoge broke 2:00 hrs the temp was 54 degrees. Sooooo, it's safe to say that 40F is too cold. Finally, as "ALL" world-class runners past and present would confirm (including myself), to "Worry" about a time trial 4 weeks out and that it didn't go as planned would be unnecessary. If training has been going well (it seems to be) and if healthy (seems to be) you simply have to check it off as an off day, especially given the fact that Jordan admitted she was cold and heavy-legged. Hmmmmm, sounds like she's just beginning to taper. Also, with a new coach, the exact tapering time may be off a bit. She's in a good spot 4 weeks out and if all goes as planned she should run well in Valencia.
My main point is not to overthink your training (let the coach do that), and just do the running and stay healthy. Now is the time to turn off your brain, recover, and get ready to race.
"Go Run One"