Selection Process Step 1: Days of Sunshine

Selection process: Step 1: Sunshine > Step 2: Temperature > Step 3: Lifestyle

To create my ranking of the sunniest cities, I focus on the number of clear days first. I start with data provided by meteoblue climate diagrams which are based on 30 years of hourly weather model simulations. These numbers are by no means 100% perfect, but they do provide a general idea of a local climate.

meteoblue provides sunshine data as the number of sunny, partly cloudy, and overcast days in a month defined as follows:

  • clear days – days with cloud cover below 20%—this is your typical most enjoyable day with blue skies,
  • partly cloudy days – days with cloud cover between 20-80%—there’s some sun, but at times it can be obscured by clouds,
  • overcast days – days with cloud cover over 80%—there’s little to no sun.

I add the monthly numbers to calculate how many clear, partly cloudy, and overcast days a location gets each year. I then exclude any location that gets more than 90 overcast days a year.

Why 90 days specifically? Because if you want to move to a sunny destination, you want to be certain of reliable sunshine year round. Clear days are the best indicator of how sunny a given place is.

Some big cities in which people complain about the lack of sunlight get on average between 100-150 days of overcast weather a year. For example, it’s cloudy for 122 days in Toronto, 140 in Berlin and 150 in London (that’s five months of gray skies!).

If someone wants to move to a sunnier climate, they probably want a notable difference instead of just a small improvement. For this reason, to create a ranking of truly sunny locations, I decided to focus on destinations with fewer than 90 overcast days a year, which means that 75% of the year will feature sunny or partly sunny weather.

This requirement excludes many destinations in otherwise warm tropical countries that get a long rainy season like Ecuador, Malaysia or Costa Rica. While many of them are very sunny for up to half a year, during the rainy season there can be as many as 15 or more cloudy days each month. The surprising fact is that in some of them, the gray skies can be almost as prevalent as in a cold, cloudy country like the United Kingdom. If your priority is to embrace the sunny lifestyle, would you really want to live in a place that’s cloudy for several months?

For example, in Bangkok it’s cloudy for 14 days in May, 16 in June, 18 in July, 21 in August and 19 in September. This means five months dominated by cloudy weather. It doesn’t strike me as the perfect destination for someone who wants sunny weather, even if it’s warm. Now compare it to Brisbane which gets 44 overcast days a year. Even on the cloudiest month on average, February, it’s only cloudy for 5 days. In which place would you rather live if you’re seeking reliable all year round sunshine?

Why Sunshine Hours Aren’t That Useful

Often, in articles about the sunniest places in the world, the metric used to define how sunny a place is are sunshine hours. I decided against using the number of sunshine hours because they don’t paint the full picture.

If you want to move to a sunny destination, you want to know how often on average it will be sunny. What does “2700 yearly sunshine hours” tell you? It might be useful for a general comparison, but you won’t know any specifics. On average, how cloudy are the winters? How sunny are the summers? Is the great majority of those sunshine hours spread over just a few months? The number of sunshine hours won’t help you answer these questions.

For example, I could tell you that Alicante, Spain, gets 2,953 sunshine hours a year. Let’s say that you live in London, which gets 1,633 sunshine hours a year. According to these numbers, Alicante is approximately twice as sunny as London. And that’s all you’re going to learn from the number of yearly sunshine hours. It might be useful, but it’s hard to imagine what it means that a place is twice as sunny.

Want more specific information? You need to know how many clear, partly cloudy, and overcast days each location gets on average a year.

Using meteoblue climate diagrams, we know that Alicante gets 116 clear days, 195 partly cloudy days, and 54 overcast days annually. London gets 35 clear days, 180 partly cloudy days, and 150 overcast days annually. This means that in Alicante you’ll see thrice as many clear days as in London. You won’t be able to learn this information from the number of yearly sunshine hours because it doesn’t take into account the cloud cover of each location.

If you dig deeper and check information for each month, you’ll get an even more detailed picture. For example, London gets only 2 clear days in January, while Alicante gets six times more—12. If we add the number of partly cloudy days in Alicante in January (11), you get 23 days of sunny or partly sunny weather in the middle of winter. In London, there are 10 partly cloudy days in January, which means that in total, you’ll get 12 days of sunny or partly sunny weather. In other words, in Alicante in January there’s at least some sun for almost 75% of the month, while it’s less than 40% for London.

These numbers paint a much more detailed picture than annual sunshine hours, don’t they?

4 thoughts on “Selection Process Step 1: Days of Sunshine”

  1. Hi sunlitvibes,

    Thanks for your prompt reply on another topic.
    I’m not entirely agree with you that sunshine hours is not a good source of information.
    I will try to reply below to your answers :
    1) On average, how cloudy are the winters? – it could be easily calculated if we take sunshine hours per month and divide to the number of daylight hours and it gives us approximative number of days/hours of daylight with/without sunshine. At the end we look for the sunniest place, which enjoys most sunshine in the concrete location.
    For example: Nicosia in January has 189 hours of Sunshine( and daylight hours around of 320-330(, so it’s sunny around of 56-57% of time, which means that 43% of time it’s cloudy.
    Denia, on other side has 185 hours of Sunshine( but has less daylight hours around of 300, so it is sunny around of 62% and cloudy 38%. So Denia enjoys more sunshine than Nicosia in winter period. And we could do the same calculation for any city which has monthly sunshine hours.
    2) How sunny are the summers? – the same calculations we could do for summers as well.
    3) Is the great majority of those sunshine hours spread over just a few months? – and again it could be easily calculated using this formula.

    I think the main issue with the partly cloudy days is that it doesn’t tell how much sunshine you will get during each day, so it could be that in one location most of partly cloudy days are at level of 70% and in another location at 20%, and it’s completely different weather. With 20% of cloudiness you could plan to go to the beach, but with 70% most likely not.

    Looking forward for you comments.

    Best regards.

    • It all depends on individual preferences. For me, it’s easier to determine it with the number of days. As long as there’s some sun, that’s easier for me to understand that there’s “x” hours of sunshine a month.

      Also, the reason I chose this is that Meteoblue has data for every single place on Earth. It’s very hard to find sunshine hours for many places and the definition of “sunshine hours” also varies depending on who calculates it (Is it a sunshine hour if it’s 70% cloud cover? Is it a sunshine hour if there’s sun for 31 minutes out of 60 minutes? Or does it have to be a full hour?)

      Sunshine hours also don’t say whether it’s bright skies or partly cloudy.

      • Regarding the sunshine hours(SH) definition there are tools and standards which should be used for collecting this data.
        Here is the general explanation what does it mean an hour of sunshine:

        But overall, I’m agree that sunshine hours it’s something that is hard to find for any place on Earth.
        Currently, I’m searching for good web sites/portals which have more information about that.
        For example, information from airports around the world represent trustable source of information and could be relied on.

        I’m more convinced that sunshine hours is more representative than overcast days, because there are tools which could tell exactly how much sunshine specific location gets.
        It’s the same like the precipitation rate measured.
        I think SH should be the main characteristic for the comparison and if there are no trustable sources of sunshine hours than we could opt for overcast days.
        If there is a good source of this information it will be exact value and not approximative like with overcast days.

        Best regards,

        • Most developed countries offer such data but not for every city. What I rely on (meteoblue data) is just a model so it’s definitely not as accurate as real-world data but then again it’s just historic data and we still rely on averages. Either way, both methods help identify the sunniest regions and then it’s down to other factors less related to weather.

          Thank you for your comments, Nikolai!


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