DeepZoom Global Ocean Winds shows animated winds and windroses for non-polar ocean regions.
Scroll and zoom the map to a region of interest and then start the animation by pressing the play button. Hover or click on the map to select a 0.25° x 0.25° rectangle and display a windrose for this region for a two week period of time.
How to read the windrose
When Columbus departed Palos de la Frontera in August 1492 he probably encountered winds as shown at left for most of the journey.
The length of each bar shows the percentage of time the wind blows from that direction between Sept 1st and Sept 15th.
The length of the colored rectangles within each bar indicates the percentage of time the wind blows with each velocity range.
So in this case, the longest bar shows that the wind was blowing from the NorthEast 64% of the time.
When the wind blows from the NE, about 30% of the time the velocity is in the between 15 and 20 knots, which is the length of the yellow section of the NE bar.
Columbus was likely sailing straight downwind.