The effect may not be quite so pronounced as it is out in the garden, but as the seasons change, so the look of our rooms tends to change as well. At different times of year, rooms get different light. A west-facing living room might get virtually no natural light in winter as the sun will set before it is that far round the house. However, in summer, you might get long hours of sunlight and the room will look slightly different as a consequence.
No matter what the wattage of our bulbs, natural light is a great deal more powerful than artificial light and it can mean we perceive colours in a slightly different way. What might in winter seem like perfect, complementary colours, could seem slightly off in summer.
If you find this has happened with regards to your rug, there’s no real problem. You don’t need to redecorate your entire room – you just need a new rug. There is no need to throw away the old one. Instead, you can have a summer rug and a winter rug and swap them round according to the time of year.