At temperatures below 50° F, wasps have difficulty flying. So when it comes to spraying wasps, it is safer and more effective if the temperature is below that mark.
As per Hunker.com, wasps are active during the day and dormant at night, which makes night time the best time to spray. Do not spray at dusk or dawn, even if the sunlight is minimal, as wasps are more likely to attack in any sunlight.
Wasps are extremely reactive to light, so when spraying in the dark, do not use flashlights or artificial light of any kind. Long-range wasp sprays, which can be applied at 20 feet, are safest when spraying in the dark.
Wasps will die out in the winter months, so if a nest is discovered in the late fall spraying may be unnecessary.
We all know that wasps can sting repeatedly, but here are some facts about wasps which you may not know shared by Rentokil.