When the weather is muggy and when there is standing water around, mosquitoes are usually present. This bottle of citronella oil, when poured into a tiki torch lamp or comparable device helps scare mosquitoes away.The ability for mosquitoes to be repelled does depend on the season. If it is fall and they want to desperately reproduce, this can be of no use, or I should say little use. However, early in the season towards the beginning of summer or end of spring mosquitoes are indeed repelled. Therefore, the effectiveness of this bottle of citronella oil does depend on how desperate mosquitoes are to reproduce.Overall, I still do recommend this bottle of torch filled citronella oil because it smells great and it was effective in my use case.