In weather fit for a polar bear, catcher Evan Gattis and a trio of bear-suit-wearing fans of the Braves rookie had quite an afternoon Tuesday during the first game of a doubleheader at frigid Coors Field.

Gattis started the fourth inning with a homer that snapped a 3-3 tie and sent the Braves to a 4-3 win against the Rockies in a game played after six inches of snow was shoveled off the field.

It was 23 degrees for the first pitch, the coldest game in Coors Field history and the coldest major league game anywhere during the 23 seasons since Stats Inc. began to keep official weather data.

“I think I was built for altitude,” said Gattis, who once spent seven months in Boulder, Colo., and worked one winter as a ski-lift operator at nearby Eldora Mountain. “I like the way my body feels here for some reason. I don’t know why.”

Justin Upton hit his majors-leading 10th homer in the first inning. Reed Johnson went 4-for-4 with three doubles, and Dan Uggla added a two-run homer into snow-covered trees beyond the center-field fence for the Braves, who snapped a three-game losing streak.

The three 20-something guys in white bear costumes about 20 rows behind the Braves’ dugout went to high school with Gattis outside Dallas. They’re thrilled for their pal’s success, and outside their bear suits they wore Braves T-shirts with “El Oso Blanco” — Gattis’ nickname, Spanish for the White Bear.

“It’s exciting, fun,” Gattis said. “Glad they got to come out. The suits are funny. … I hung out with them last night. My family’s in town, too.”

Gattis’ mother, Melinda, sat near the bear-suited guys, and his twin sisters, Valerie and Vanessa, and aunt Gayle were at the game.

He leads major league rookies with six homers, including an National League-leading five on the road. Gattis has homered in all five major league ballparks in which he’s played, and Tuesday’s homer was good for his fifth game-winning RBI. The only major leaguer with more than five before Tuesday was the Giants’ Angel Pagan (six).

Staking Mike Minor (3-1) to an early lead was key in the first game of a day-night doubleheader against the Rockies, who had lost once in nine home games before Tuesday. Colorado had the highest home slugging percentage in the major leagues and began the day tied with the Braves for the majors’ best record (13-5).

“You always want to get out ahead,” said Upton, who homered with two outs and none on in the first inning, “but to let Mike settle in and know that he didn’t have to be too perfect — he could settle in and do what he was trying to do in his game plan. That helps him a ton and it helps us.”

Short-sleeve-wearing Minor pitched six strong innings — five hits, three runs, two walks, five strikeouts — and the Rockies mustered one hit in three innings against relievers Luis Avilan, Eric O’Flaherty and Craig Kimbrel, who had two strikeouts and earned his eighth save.

Minor said he feels “restricted” pitching in long sleeves, so he went with his usual T-shirt beneath his jersey. His only concessions to the extreme cold were tights beneath his uniform pants, and deep-heating rub applied to his back and pitching arm by Braves head trainer Jeff Porter.

“My skin was burning,” Minor said, smiling. “I never used that stuff before.”

Braves manager Fredi Gonzalez said, “Mikey really did a nice job. He did a terrific job pounding the strike zone, fighting the elements. We scored some runs early and were able to get another one late in the game after they came back and tied it, and our bullpen did a terrific job.”

Minor entered with a 0.95 ERA and allowed as many runs (two) in the second inning as he allowed in 19 innings before Tuesday. Atlanta native Dexter Fowler tripled to start the third inning and scored the tying run.

Gattis didn’t waste any time putting the Braves back on top with his homer to start the next inning.

In the ninth, Wilin Rosario hit a one-out single against Kimbrel. One strikeout later, Rosario tried to steal second, and Gattis made a strong throw to Uggla, who applied the tag for the final out.