SOUTHPORT, England — Sean McLean leaned back in his chair and turned to the right, his gaze locking in on the row of flapping flags perched atop the grandstand behind Royal Birkdale’s ninth green.On Thursday, the sleep-deprived course manager — the keeper of Birkdale’s venerable turf — began to speak of the unusual eastward wind gracing the Open Championship venue. But then he stopped himself. Something out the window of the pavilion he was seated in had changed.“It’s actually swung round off the sea again,” McLean said, eyes widening. “Aye, heat can do strange things to weather in general.”Weird is part of the deal at this year’s Open, and the players, course staff and Royal Birkdale’s consulting architects are feeling it. All at once.“You can’t plan for these conditions,” said Tom Mackenzie, the co-founder of Mackenzie & Ebert, the design firm that led the renovation of Royal Birkdale ahead of this year’s Open. “You just absolutely can’t.”That’s because the host country is scorching. Here in Southport, a seaside town on the Merseyside coast of England, the hundred-year-old buildings were constructed with the sole mission of trapping in winter warmth. Air-conditioning units are prized possessions. The dozens of courses that litter the region take on rain storms and gusts like it’s nothing.So, a record heat wave — with temperatures reaching a high of 82 degrees Fahrenheit earlier this week — will naturally throw things for a loop. The pressure in the air is causing the winds to act in ways the club rarely sees. Thousands of fans are flooding through the gates with sunscreen in their packs rather than wool hats. And Royal Birkdale is literally baking.Why is this golf course’s bunker shaped like a donut?Gabby Herzig and Lauren Morales-JonesGolden brown hues dominate the links surface, the rare bits of green centered around sprinkler heads. The turf is hardening. The putting surfaces are sounding more like corkboards by the hour. Royal Birkdale is hosting its 11th Open Championship this week, but it hasn’t seen conditions like this for the tournament since 1976. That year, it was so dry and hot that a suspected cigarette butt caused a fire to ignite between the first and second fairways, holding up play for 40 minutes. Viewers would be a lot more familiar with a wet and cold Birkdale, like the one Jordan Spieth conquered during its most recent hosting duties in 2017.It’s no 1976, but the test that the Royal & Ancient expected in 2026 is rapidly evolving, and it will continue to do so throughout the week. There is not a single drop of rain forecasted for the next three days. McLean and his team are working around the clock, sprinkling water on the course only in the mornings and evenings, barely enough moisture to keep the blades of grass alive.