Just did my 4k time trial today.
Here are the splits:
1st km: 4:06
2nd km: 4:19
3rd km: 4:24
4th km: 4:26
Similar to my PB last month, but was 21 degrees celcius then. Heat is extreme nowadays in my area, 33 degrees celcius during this run. Evening though, so it's fine with me. About to be done with 1week of buildup.
P.S. worked out my training paces using the http://www.time-to-run.com/training/10k/programtips.htm
Everything's pretty much the same.
Looking forward to sub40 10k training!!! Very excited!