One way to look at it would be to practice while the energy around you has calmed. For instance early in the morning (anytime), before traffic starts up and the hustle & bustling start. Also in the evening after everything begins to settle down and there is calmness in the air.
The peak times for meditation previously mentioned which were around 11 to 12 morning or Evening would be nice.
There are other beliefs that prim time would be in the am with the sun rising or just before dusk. Similar to the above when the energies of the area/world are calmest.
Personally I think some combination of the above would be best. There is nothing like connecting with the energies first thing in the morning with the sun rising. But weather and real life schedules does not always permit such luxuries.
Realistically most people would find what works for them and stick to it. Ultimately anytime is beneficial as long as you are consistent, persistent and dedicated.
