Alt Tab to Active Sky X. Find nearest weather station winds, and find the altitude with the least of a headwind or even most tailwind.

If using default real world weather, alt tab and go onto the net and find METARS.
But the best way is to avoid going at an incrorrect altitude is not going to that in the first place.

Before every flight, go to,
www.flightaware.com and search for recently used IFR routes. Type in your departure and arrival and note the altitudes the aircraft take, however, it's a good idea to travel at the optimium altitude for your aircraft and weight, so take that into consideration.

One more thing, east bound flights fly at odd flight levels, west bound flights fly at even flight levels.