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Because of all the heat fueling convection cells, Venus has some brisk winds especially in the upper atmosphere (up to 370 km/h).

I realize the winds are quite slow at the surface, but are there any latitudes with more moderate winds at the 50 km level?

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    $\begingroup$ fascinating question, i immediately wonder about Mars now. $\endgroup$ – DrZ214 Jan 30 '16 at 5:28
  • $\begingroup$ @DrZ214 in my understanding Mars is all doldrums. Not much wind at all. Because of a deficit of heat and atmosphere. $\endgroup$ – King-Ink Jan 30 '16 at 5:31
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    $\begingroup$ Could be. But despite the small atmosphere, Mars does have large windstorms that can cover almost the whole planet. I'm pretty sure this is a frequent occurrence (at least a few times per Martian year). Once there was even a little dust devil (mini tornado) that came along and cleaned off the dust from a rover's solar cells, extending its life. $\endgroup$ – DrZ214 Jan 30 '16 at 5:33
  • $\begingroup$ The winds quickly decrease towards higher latitudes, eventually reaching zero at the poles ! en.wikipedia.org/wiki/Atmosphere_of_Venus#Circulation. $\endgroup$ – Conelisinspace Aug 27 at 17:07
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There are no horse latitudes on Venus, only equatorial doldrums and polar fronts / collars. Convection driven Hadley cells on Venus stretch to ±60° in latitude from the intertropical convergence zone to North and South polar collars, so no subtropical latitudes high pressure areas. From Wikipedia on Atmosphere of Venus - Circulation:

enter image description here

This is quite a bit different to formation of subtropical anticyclone zones between trade winds and westerlies on Earth:

              enter image description here

And average wind speed at 50 km altitude on Venus is between 55 and 70 m/s (200 to 250 km/h). From Geoffrey A. Landis' Exploring Venus (PDF):

        enter image description here

Comparison of winds measured by radio tracking of probes below 60 km with winds estimated from the measured pressure by means of the assumption of cyclostrophic balance. Above 60 km, the winds are inferred entirely from measured pressures.

If you're curious about this for the purpose of aerobot exploration or aerostat colonization, you would be advised to increase your altitude above the sulfuric acid clouds reaching to about 60 km altitude, but properly shielded craft (e.g. high density PE plastics are resistant to it) shouldn't have these problems also lower, unless they're solar powered, at which point you'll again have to aim higher. Refer to Geoffrey A. Landis' work on Venus aerostat colonies and the latter part of my answer to What useful materials can be extracted from Venusian atmosphere? for more info.

Equatorial doldrums, even if they're fast, should be fairly stable though, again something I already discuss in my answer to A cloud-top colony on Venus, will it drift to the poles?, in particular in the part about the observed path taken by the two Vega program balloons, both released at near-equatorial latitudes. Balloons traveled at an average altitude of 54 km for roughly 46 hours and navigated about 1/3 the Venusian circumference. That comes out at average speed of ~ 278 km/h. Not 370 km/h, but not exactly a mild breeze either.

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  • $\begingroup$ Nice answer but what about the reason why? Isn't it because Earth is inclined but Venus has almost no inclination? (or almost 180 degress inc if you define it that way, since it rotates in the opposite direction as Earth.) $\endgroup$ – DrZ214 Jan 30 '16 at 5:29
  • $\begingroup$ @DrZ214 Earth's inclination only has an effect in summer and winter. At the spring and autumn equinoxes it has no effect, so I doubt that that is relevant. Venus's low rotation rate may be highly relevant. I'd love to see what the reasons for the different circulation patterns are. $\endgroup$ – Level River St Jan 30 '16 at 7:17
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    $\begingroup$ @DrZ214 You must mean axial tilt, not inclination. Yes, but that could be a question on its own. In a nutshell, it's how spherical harmonics play out for Venusian atmospheric density, composition, heat capacity, rotation rate, and planet's mean distance to the Sun. For example, eddy diffusion occurs a lot slower on Venus than it does on Earth, gravity waves (not to be confused with gravitational waves) have much lower frequency and amplitude, it's more viscous,... there's just less mixing. You can find more if you search NTRS for "venus atmosphere spherical harmonics". Or ask a new question ;) $\endgroup$ – TildalWave Jan 30 '16 at 13:48

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