Why are grey days depressing?

Thanks to Meghan Markle openly talking about thoughts of suicide, depression is something people are talking about for the moment. I'm sure that it will soon be relegated back to whispers and closed door conversations, but for now we can think about it in terms of healthcare and not just mental healthcare.
Before I get into this post, I have to remind you that I'm no expert on anything related to depression or mental health. In fact, I'm not an expert on anything at all. I do not suffer from depression, so I can't even offer any first hand observations. These are just some thoughts and observations that enter into my head and make me wonder about stuff.

Long winter nights, long winters, overcast days, periods of grey, rainy days, all seem to have a way of triggering depressive swings. A lack of exposure to direct sunlight seems to have a very negative effect on most people -- not just people that suffer from depression.
One of the aspects of becoming more contemplative is asking myself -- Why? Why is it this way and does it have to be this way? Can a change of perspective bring about a change of attitude or outlook?

Sometimes I have to remind myself that God moves in the darkness as well as in the light. Genesis teaches that before God created light there was only darkness and in the darkness the Spirit of God moved. When God created light, He didn't do away with darkness -- He separated darkness from the light and called the dark - night, and the light - day. Each has its own purpose and both are necessary.

Nights give us (and most of the plant and animal life) the rest we need. Some things thrive in the night and darkness is their active time. The night is a necessary part of the balance of the earth's life cycles. 
Just as we need dark nights, we need the rain. The rainy days are necessary to replenish and refill the life giving water reservoirs. The rain waters the food crops and the flowers that feed the bees, butterflies, and birds. Isn't it funny how we see a beautiful flower and think of the sunshine that brought it into being, but rarely think of the rainy days and restful nights that were also a part of its beauty and creation.

To be fair -- 
This morning I am enjoying sitting in the sunshine. I hope that I will also enjoy the rainy mornings that are surely in my future. I am a fan of overnight rain showers. The earth being watered while I sleep is perfect -- a rhythmic sound to sleep by, the needed water for life, and we still get to enjoy sunny days for play and work! (I wonder if nocturnal creatures wish it would rain during the day when they're sleeping!)

Maybe if we started to see grey, rainy days and long dark nights as a necessary part of life they would begin to feel less depressing. I'm not advocating that curing clinical depression is as simple as eliminating some of the triggers. I know far too many people that need the chemistry of medical science to deal with their depression. These are just thoughts that help me with those particularly depressing kind of days.

If your depression is more than feeling bad on grey days, please seek professional help. We are slowly moving past the dark times where mental illness is stigmatized. It helps when well known people and celebrities are able to come forward and make mental illness issues as common as other illnesses. Please use the moment to talk to someone that can help you. 

Sorry for the rambling this morning.
I hope that you enjoy your day.

John