I’ve been cross-country skiing in Chicago for a quarter century, since the days when winter was winter, before global warming put a squeeze on the number of snow days. The flat Chicago Lake Plain is a perfect surface for cross-country skiing — all glide and no grunt. Here are four of my favorite spots.

Skokie Lagoons

There are two ways to ski this. On an ordinary winter day, take the trails that wind like ribbons around the chain of lagoons on the upper reaches of the Chicago River. On a day when the temperature is close to zero and the ice is thick, ski on the lagoons themselves.

Sagawau Nordic

This is the spot for the beginning skier. The Sagawau Environmental Learning Center, located in southwest suburban Lemont, rents skis for $15 a person, offers lessons for $20, and grooms the trails, just like in the Winter Olympics. 

Sydney R. Marovitz Golf Course

The best place to ski along the lakefront. Undulating but not hilly, and deeply carpeted by lake-effect snow. The Lake View course is not groomed, though, so you’ll have to carve your own tracks. 

Palos Trail System

This one is for the adventurous Nordic athlete: 42 miles of trails, taking skiers around trees, over roots, and up and down hills in the southwest suburbs. Truly the winter version of cross-country running.