Titan swung endlessly about its primary. Nine-hour days succeeded nine-hour nights of unbelievable ferocity. The eternal wind howled and bit and tore, and the shifting ice mountains heaved and roared under Saturn's tidal drag.
Sometimes, during the day, the pair ventured into the open, fought the boisterous winds, clung precariously to frigid slopes. Once Diane was swept bodily away, saving herself miraculously on the verge of one of the deep and mysterious crevasses that bounded their mountain slope, and thereafter they were very cautious.
Once they dared to penetrate the grove of rubbery and elastic whiplash trees that grew in the shelter of the nearest cliff. The things lashed out at them with resounding strokes, not violent enough to fell them, but stinging sharply even through the inch-thick layer of sponge rubber that insulated their bodies from the cold.
And every seven and a half days the wind died to a strange and oddly silent calm, was still for half an hour or so, and then roared with renewed ferocity from the opposite direction. Thus it marked Titan's revolution.
At almost equal intervals, every eight days, the native appeared with the clock. The creature seemed unable to master the intricate problem of winding it and always presented it mournfully, brightening at once as Diane set it ticking again.
There was one impending event that worried Tim at times. Twice in its thirty-year period Saturn eclipses the Sun, and for four Titanian days, seventy-two hours, Titan is in utter darkness. The giant planet was nearing that point now and would reach it long before the rocket ship, speeding from the Earth at perigee, was due.
To say that I'm finding it fairly difficult to work with is an understatement - it's vitally important to the plot of the only story Weinbaum set there, but I can't figure out any easy way that it works.
Basically, in the real universe Titan is tidally locked to Saturn, and takes 16 days per orbit. Saturn rotates in 10.6 hours. Titan is eclipsed fairly often, and in multiple orbits when it happens, but the longest eclipse is only 6 hours.
Now, if I ignore the exact times given I can more or less explain this by a rotating Titan and some sort of climactic shift when Titan is nearest and furthest from the Sun. The eclipse thing can be handwaved away, I think. But I need a mechanism for the regular climate changes and I can't think of anything obvious.
Titan is described as having a dense atmosphere, mostly Xenon plus some oxygen, if that helps. I'm assuming that it gets some of its warmth from Saturn (which in the Weinbaum universe is moderately hot), some from internal radioactivity, and some from the sun.
Any suggestions? Or should I just begin "for unknown reasons..."?
later just realised that if I say Titan has an axial tilt I can explain most of this as seasons related to the heat received from Saturn and the sun, similar to the shifting of the trade winds on Earth. If I keep it vague is it vaguely plausible?