Talwin

Originally published on Poul Anderson Appreciation, 28 May 2012.

In the Wilderness between the Terran Empire and the Merseian Rhoidunate, the system of the star Siekh includes many asteroids but only four planets, including Talwin: 

eccentric orbit, probably disrupted by early passage of another star;
distance from Siekh varying from 0.87 astronomical units to 2.62 a.u.;
three degrees of axial tilt;
planet-wide seasons;
twice-Terran year;
six month summer, six week autumn, fifteen month winter, six week spring;
eighteen hour day;
no moon;
blue vegetation;
ankle-high equivalent of grass, called wair by Merseian explorers;
many scattered islands;
one continent (400 kilometers wide, wedge-shaped, stretching from north pole to equator, divided by an east-west mountain range);
huge icecaps forming, extending 45 degrees, then melting each year;
spring floods;
in summer, snowless mountain peaks, northern swamps, boiling southern lakes and rivers;
Domrath, winter hibernators, feast and copulate all autumn;
Ruadrath estivate as sea animals all summer.