In the second step of my selection process I look at the mean daily maximum temperature of the coldest month. I filter destinations that don’t reach on average at least 15 °C (59 °F) so that during a winter day you’ll rarely have to wear anything more than a long-sleeved shirt, a light jacket, or a thin sweater.
This requirement excludes some slightly colder sunny destinations like Malta, south of France, and most of Italy (except for Sicily) where mean daily maximums in the coldest month don’t reach 15 °C (59 °F).
If you want to move to a sunny destination, you want it to be warm throughout a year, don’t you? 15 °C (59 °F) is not a particularly high temperature that would exclude many destinations, but it’s still mild enough. If such temperatures occur only during the coldest month, you don’t have to worry that any of the destinations in my ranking will be too cold year round.
Why I Don’t Filter by Any Other Criteria
Temperature is a highly personal preference. The winter daytime temperature filter ensures that the destinations in the ranking never get too cold during the year, which I found to be one of the key requirements of people wishing to move to a sunny place.
I decided against using any other filters (such as maximum temperatures during the summer or minimum nighttime temperatures), because it could eliminate too many destinations.
For example, some people hate extremely hot summer days in Arizona, while it doesn’t bother others that much. As for cold nights, they can happen in almost every climate (including Arizona, which is one of the sunniest places in the world) except mostly for the tropics. For this reason, I don’t use any other temperature filters as they would make the list too short to be useful.
Other factors like humidity and wind also affect how we perceive the temperature, but for the purposes of the ranking, I decided to ignore this factor and mention it individually when reviewing each specific location.