Got up earlier today, and did this run in the daylight.
I intentionally tried to go "slower and steady" but was barely down on my pace of W7R3. I did keep my pace stable for most of the run - thanks to another runner, I think, whose pace seemed to exactly match mine. I kept five or six metres back and used them as a reference point. Seemed to help!
Getting to 25 minutes still required a bit of willpower, and I was swearing silently through the final 3 minutes, at whoever thought up this grand idea... Kept running, didn't slow down, until Runmeter said "Run completed" at me, and suddenly all my bones melt and its hard to walk straight... Oh thank goodness. 4.18 km of running. Phew!
One lesson - next daytime run in Shenzhen, get up earlier to run before the sun gets high enough to see over the skyline. The air temperature was only 29 degrees, but with a clear sky the direct sunlight was utterly baking. There are plenty of trees in the park, so the squiggly-return section of the root is almost all shaded, but the initial straight has only a single line of trees which no shade at all. Apart from one of the nearby skyscrapers, which cast a finger of cool shadow across the middle segment of the long straight. Thank you, skyscraper architect person!
My feet and knees are definitely feeling the extra distance, so I will make sure to get some good rest before trying W8R2 on Tuesday evening. Back to night runs for me.
Picture above is the south end of the main straight, looking north.