Getting enough sunshine can have a powerful impact on your mood and overall mental well-being.

Many people find that a sunny day lifts their mood like nothing else. Culturally, we associate sunshine with happiness and relaxation — and as it turns out, there’s science to back that up.

Over the past few years, as awareness of conditions like seasonal affective disorder (SAD) has increased, people have become more conscious of the link between weather and mood.

We know that a lack of sunshine can have a negative effect on mental health, and that the reverse is also true.

All kinds of things in our environment can affect our mental health, from pollution levels to the amount of greenery we can access. The weather is no exception.

Research across different countries and climates has long suggested that there’s a seasonal pattern to depression.

So if you live with a mental health condition, keeping track of the weather could be an important part of your self-care plan.

There’s mixed evidence regarding the sun’s effect on depression. Our bodies need direct sunlight exposure in order to create vitamin D (aka “the sunshine vitamin”), which plays a major role in regulating mood.

Vitamin D supplementation has been shown to improve mood, and many people with depression also have low vitamin D levels, which suggests that there may be a causal link.

Therefore, getting enough sunshine may help the symptoms of depression, by regulating vitamin D levels.

A study from 2009 indicated that a lack of sunlight increased the risk of cognitive impairment among people with depression.

But a 2021 study produced more mixed results. The researchers found that exposure to sunlight over the long term (that is, a 30-day period) had a beneficial effect on people with major depressive disorder.

More short-term exposure to sunlight, though, actually had a negative impact on mood, possibly because it interfered with people’s sleep-wake cycles.

Remember to wear sun protection when you’re the sunlight, such as sunscreen or sunblock with SPF 30 or greater, and protective pieces of clothing such as hats and long sleeve shirts.

Serotonin is a neurotransmitter that plays a role in several key bodily functions, including sleep, digestion, and mood.

One leading theory of depression is that it’s caused by low levels of serotonin, which is why a class of medication called selective serotonin reuptake inhibitors (SSRIs) are a leading treatment for the condition.

But the serotonin theory is heavily debated and isn’t backed up by much clear evidence.

A lack of serotonin is believed to be the cause of SAD, which occurs during the winter. A lack of sunlight can affect the body’s production of serotonin, leading to lower levels that can, in turn, have an effect on your mood.

Sunlight also affects your body’s ability to produce a hormone called melatonin, which helps to control the sleep-wake cycle.

Being exposed to bright light in the morning seems to be especially important when it comes to regulating melatonin levels.

Sleep disturbances can be a major factor in depression. It’s common to experience either insomnia (difficulty sleeping) or hypersomnia (excessive daytime sleepiness).

Research indicates that abnormalities in melatonin production play a role in depression.

Despite the mental health benefits of sunlight, it’s important to be aware of what else might be happening on a sunny day. Sunshine often means high temperatures, which has some potential negative effects on mental health.

People who live with anxiety disorders may need to exercise particular caution. High temperatures can increase levels of the stress hormone cortisol, and may worsen the symptoms of anxiety, or make you more susceptible to panic attacks.

Recent research also shows that hot weather increases aggression and agitation. For people who live with a mental health condition that causes changes in mood or impulse control problems, this may be challenging.

We assume that sunshine goes hand in hand with a good mood, and in general, that seems to be true.

Sunlight has a beneficial effect on mental health, thanks to its ability to help our body create vital substances like vitamin D, serotonin, and melatonin.

If you live with depression and don’t typically get much sunlight, it may be helpful to try and find ways to increase your sun exposure.

If you live in a climate where that’s challenging during the winter months, light therapy is a great option that has been proven to help treat seasonal depression.

Spending time outdoors, particularly in nature, can have a beneficial effect on depression, anxiety, and other mental health conditions. So even if the weather isn’t sunny, you can reap a lot of benefits just from being out in the world.

It’s important to remember that sunshine and hot weather can also have some negative effects on your mood, depending on a person’s unique situation and history.

If you’re experiencing symptoms of depression or any psychological condition, it’s a good idea to consult a mental health professional for help as you decide what steps to take.

If you’re looking for a therapist but aren’t sure where to start, check out Psych Central’s guide to finding mental health support.