All 'longer range' weather data comes from the US run GFS model.
Many websites provide portals onto GFS; some mentioned above.
I often use the
NOAA site. It can produce various graphs for a geographical point.
Enter the airport ICAO code in the box.
Continue.
Choose GFS 0-180hrs (e.g.)
Click on Default with Winds, and Speed and Direction.
Enter the anti-scripting code in the window.
Click on Get meteogram.
That's the simple way to use it; you can choose various other parameters if you pick the Choose from Below option (but you cannot mix 2D and 3D graphs).
Other sites such as
Meteoblue can plot weather along a straight-line route.
The
PPL/IR Europe magazine has some articles describing other websites e.g.
here and
here.