vectors

[cunning otter]

if it says the wind is coming from 70 degrees is it coming from yellow or blue

[grand wagon]

If you assume 0 degrees is north and angles increase clockwise, the wind is coming from east north east

(yellow in your drawing)

[plucky meadow]

although both vectors have an angle of 70 degrees from the y-axis

you can see that the quadrant 3 vector will end up being opposite to the quadrant 1 vector