  We present measurements of the wind speeds at the nightside lower clouds of
Venus from observations by JAXA's mission Akatsuki during 2016, complemented
with new wind measurements from ground-based observations acquired with
TNG/NICS in 2012 and IRTF/SpeX in 2015 and 2017. Zonal and meridional
components of the winds were measured from cloud tracking on a total of 466
Akatsuki images of Venus acquired by the camera IR2 using the 2.26-$\mathrm{\mu
m}$ filter, with spatial resolutions ranging 10--80 km per pixel and covering
from 2016 March 22 to October 31. More than 149,000 wind vectors were obtained
with an automatic technique of template matching, and 2,947 wind vectors were
inferred with the manual procedure. The meridional profiles for both components
of the winds are found to be consistent with results from the Venus Express
mission during 2006--2008, although stronger wind variability is found for the
zonal component at equatorial latitudes where Akatsuki observations have better
viewing geometry than Venus Express. The zonal winds at low latitudes also
suggest a zonal variability that could be associated with solar tides or
vertically propagating orographic waves. Finally, the combination of our wind
measurements from TNG/NICS, IRTF/SpeX and Akatsuki images with previously
published and based in data from 1978 to 2017 suggests variations of up to 30 m
s$^{-1}$ in the winds at the lower clouds of the Venus nightside.
