Being a climate scientist is a pretty depressing job these days, since it involves predicting disaster and being ignored even when you're not getting death threats and legal harassment. So to blow off a little steam, climate researchers at the Universities of Bristol, Cardiff, and Southampton decided to create the scientific equivalent of fan fiction. The consequence is a climate model of the world in which Game of Thrones takes place.
Scouring the books for every weather reference they could find (rather a lot in a series obsessed with the coming of winter), the authors have created a climate model so detailed it explains the flight-path of Targaryen dragons across the Narrow Sea.
Sensing that a boring commitment to “fact” might make it hard to get such a paper published in the peer-reviewed journals of Earth, the authors have submitted their work to the Philosophical Transactions of the Royal Society of King's Landing. Modestly, rather than publish under their own names, they attributed the work to Samwell Tarly, who has a particularly acute familiarity with how important the Westeros climate can be.
To ensure the widest dissemination, and because too much geekery is never enough, the work has also been published in Dothraki and High Valyrian, although Tarly complains that the Dothraki not being sailors have no word for “isobar”. There is also a twitter account where citizen scientists wishing to collaborate with Tarly can contact him.
Tarly observes that, despite the different lengths of the seasons, the climate at the Wall resembles that of Lapland, while Casterly Rock is similar to Houston – a warning the Lannisters are unlikely to heed. The season length, which others have attributed to everything from sunspots to the ridiculous notion of “magic”, Tarly explains as the consequence of chaotic tumbling of the planet's axial tilt. Although Tarly is forced to guess the continents of the Southern Hemisphere, his work matches the books closely.

Chaotic axial tilt does little to alter climate sensitivity to greenhouse gasses, so emissions from dragons and deforestation for the purposes of shipbuilding may soften future winters. Desirable as this may be to keep White Walkers at bay, Tarly notes the consequences it would have on the low-lying parts of coastal cities, particularly Kings Landing. Consequently, Tarly calls on the rulers of the seven kingdoms to install windmills and use dragons sparingly.
The work follows in the footsteps of less challenging efforts by Radergast the Brown to simulate the climate of Middle Earth, noting the rainshadow of the Misty Mountains, the climatic similarity of The Shire to Leicestershire, and Mordor's likeness to west Texas. Tarly and Radergast want spoilsports to know their work was unfunded and simulations run in their spare time.

If you've ever wondered just how cold it gets in different parts of Westeros in winter, here is your answer. Dan Lunt/University of Bristol