Average Sunshine Hour Map - USA and Europe

[Chester B]

I've seen this map a few times, I'm sure its not 100% accurate but it gives a general idea of the amounts of Sunshine in the two regions. 

[Mazat]

Ryan, this is a very interesting topic 😄and also important with regard to the whole climate everywhere.

someone explained to me a few years ago that depending on the amount of cloud cover there are more hours of sunshine or less. with regard to the sky being bright blue, this results in more hours of sunshine. this would explain why there are more hours of sunshine in a desert than elsewhere.

one factor is certainly also the vegetation. if there are more trees, there should theoretically be more evaporation, and later more precipitation, if i am thinking correctly. more precipitation would mean fewer hours of sunshine.

i would have to look it up, or maybe someone knows. in a dense jungle there should therefore also be fewer hours of sunshine, leaving out the average annual air temperature. 

there are certainly many other factors such as the geographic location of the measurement sites. Day length of the respective location etc.

yes, and it seems to be a fact that the usa, let's put it this way, simply has many more hours of sunshine in most areas than most regions in europe. 
the south of europe can certainly keep up to some extent, depending on which region you compare or contrast it with.

that was just thinking out loud ...

 

[Marco67]

In a way Europe can be considered a Eurasian peninsula, which is surrounded by water (Atlantic Ocean, Mediterranean Sea, Baltic Sea, and Black Sea). This results in more cloud cover and a milder overall climate.

Also, Europe is for the most part on the same latitude as the Northern US and Canada.

[Sabal_Louisiana]

While the US map seems reasonable,  some of these graphics often rely on terribly outdated and sparse data.

In the US, The issue is that almost no NWS or FAA met stations record sunshine duration anymore, and haven't done so in quite some time. A sunshine recorder, or even a pyranometer, is not that expensive but for whatever reason, they have neglected to use them.

However,  most report sky cover (based on oktas). A rough inverse relationship exists between the amount of sky cover and sunshine duration. So you can get an 'idea' how sunny or cloudy a particular location is.

Satellite technology has evolved to the point that we can now estimate cloud cover (sunshine during the day being the absence thereof) over a time series for practically any point on Earth. It has been determined from such grid data, for example,  that the sunniest area on Earth is most likely around where Egypt, Libya and Sudan meet in the Sahara. The sun typically shines there at least 97% of the time.

There are countless agricultural and personal weather stations throughout the World and are particularly abundant in the US and Europe. Their data is usually publicly accessible. Many have a solar radiation sensor. Ideally, one could measure sunshine duration if the sensor measures direct solar radiation. The WMO standard for sunshine duration is whenever direct beam radiation exceeds 120 w/m2. and tallied in .1 hours.  But, the solar radiation value that is almost always recorded on PWS and on mesonets is global (total) solar radiation (direct+diffuse), which makes it harder to figure out if the sun was sufficiently shining when the measurement is taken. Still, by using certain formulas, one can approximate sunshine duration from recorded global solar radiation if the sensor is accurate, the location unobstructed, and enough readings are taken in a day. 

Electronic sunshine recorders and pyranometers can be purchased by a weather enthusiast if they would really like to datalog sunshine duration for the desired location.

We can reasonably estimate sunshine duration for many places using these methods. 

[SueinAZ]

365 days of sunshine per year here. Though the map above lacks detail, 50 miles fron here they get a lot of clouds and even some rain during monsoon season, but this detail is not shown. 

[SueinAZ]

Sunburnt lemon and burned leaves

Sunshine days are the same historically, but Sun seems hotter as seen through plant damage. This tree produces around 70 lbs of lemons, but these cooked ones are discarded.

[Mazat]

On 8/10/2025 at 2:08 AM, SueinAZ said:

Sunburnt lemon and burned leaves

Sunshine days are the same historically, but Sun seems hotter as seen through plant damage. This tree produces around 70 lbs of lemons, but these cooked ones are discarded.

Good observation, Sue.

A well-known cactus grower here, who is now over 85 years old, told me that the sun's rays have become stronger. He and his wife noticed this because they had a roof over their cactus and succulent hall that they could close, like a tennis court, or adjust so that plants that needed less light/sunlight could be regulated.
Unfortunately, I only met them both five years ago and saw them briefly at that time. After these visits, he sold everything, naturally due to his age.
He had several thousand species of cacti and succulents and many other exotic plants. All the plants originally came from seeds that they collected on their travels around the world and used to build up their collection.
He had the hall in a much cooler climate near St. Gallen. He also had species planted outside around the hall.
It's a shame I didn't have more time to take everything in at the time... 

At the time, I was working so much that I hardly had any time, except for our palm trees and exotic plants.

They also sold some plants, as the rent for the large hall was horrendous...
The prices were rather high, even for the smallest plants, which quickly cost USD 15 per plant.

[SueinAZ]

I have been thinking of covering this tree, but that would cut down on photosynthesis to feed the fruits. I could bag the individual fruits in June to block sun and try to prevent cooking the lemons on the upper branches. 

[mnorell]

31 minutes ago, SueinAZ said:

I have been thinking of covering this tree, but that would cut down on photosynthesis to feed the fruits. I could bag the individual fruits in June to block sun and try to prevent cooking the lemons on the upper branches. 

Many plants will suffer photosynthetic overload and Citrus are no exception. Your best bet is to plant a taller shrub or tree on the west side of that lemon. This will protect the trunk and branches (citrus bark/cambium is very sensitive to desert sun-scald) as well as the leaves and fruit. Any burn like this is a signal that the plant needs more shade...so you shouldn't be worried about cutting into its photosynthetic needs...it is actually the other way 'round. Depending on the size of your lemon tree, you can plant something like Senna alata (super fast-growing, beautiful and tough, and is wonderful cover for just about anything you might put in the ground), and for more height, fast-growing feathery legumes like Lysiloma, Albizia lebbeck, et al., these will protect the foliage without cutting light out too severely and these latter two I mention have the added benefit that they're nitrogen-fixing and will enrich your soil, which will also benefit your citrus.

[Silas_Sancona]

2 hours ago, SueinAZ said:

I have been thinking of covering this tree, but that would cut down on photosynthesis to feed the fruits. I could bag the individual fruits in June to block sun and try to prevent cooking the lemons on the upper branches. 

My neighbor's Lemon has been suffering the same damage over the last 3 summers, even after i went and painted the entire trunk / larger branches ( Was suffering moderate sunburn before i applied tree paint ) ..and dug a large and deep trough around it, out to the edge of the tree's canopy. Deep water once every 2 weeks ( to a depth of a foot < depth of the bowl i built > 

Even with doing what i can to keep it going,   ...May ...or may not..  last another year.. 

Fruit that is on it right now,  that looks good?  ..is on the " shady " side of the tree.




Folks who move here often greatly under estimate just how nasty the combination of ( almost ) endless, intense sun, + the heat this time of year is ..esp. when it doesn't rain ( Only got sprinkles here tonight )  when it is supposed to. 

Always tell people thinking of moving here " Pick a house / property with lots of high tree canopy on-site  ..Tree canopy provided by trees that can handle our heat.. 

" No   ...or barely...  any tree canopy to provide shade in your yard?  ..everything you plant will experience some deg. of burn during the summers, ..even some native stuff..  




A different neighbor on my block has a Fruit Forest planted under high canopy of 4 or 5 Sisso Trees   ..Inc. some stuff that is quite sun sensitive, esp. here.  98% of it looks pretty good right now. 



Ficus nitida / microcarpa we have in our yard  -which is the only tree back there providing -any- shade to stuff i have tucked under it?  

...Looks like someone took a blow torch to the entire top of it's canopy.  ...It is 25ft tall,  w/ a canopy about as wide..  Have a ton of dropped leaves to clear out once the heat finally backs off. 


Is experiencing worse damage than it did last year, ..or in '23  ...Or during any winter " cool " spell i've seen since moving here. 

Watering everything  about 2x's a week right now, inc. the back Lawn area next to the Ficus.  Not a chance in h**  it is not getting plenty of water. 

If this were my house instead of a rental,  i'd be working on getting 3 more trees up  to provide shade / high, overhead canopy to the entire yard ( Our back yard faces west..  Both neighbors across the alley have no trees on their property  ..so that side of the house bakes in the afternoon this time of year. )