So when they're fat and happy they're good natured. Nectar flow would be when there is plenty of food for them to gather, good weather and flowering plants-a-plenty?
Some general guidelines on inspecting hives.
1. Do not wear perfumes, toilet water, or other substances that have odors, the more pungent the nastier the bees get.
2. Don not drink Coffee, Alcohol, chew tabaccy, imbibe any beverage that contains caffiene (soft and sports drinks).
3. Move with slow deliberate motions, haste is the enemy of a beekeeper, develop BEE ZEN--AAaauuuuhhmmmm!
4. The warmer, clearer the weather the more docile the bees will be because most foragers will be out working.
5. The stronger the flow the more docile the hive--see #4.
6. An active hive us usually too busy to worry about the small stuff--see #4.
7. Crushing a flower in your hands or using something like talc to cover your own odor helps keep stings away.
8. Always wear a veil, gloves are optional and clumsy, latex of nytral gloves leave more dexterity.
9. If stung remove the stinger with the blade of the hive tool, don't pull it out with your fingers as this just squeezes more venom under your skin.
10. Spend several hours learning how to keep you smoker lit before you actually have to use it.
Good Luck and Have Fun.