These late spring days offer some of the best sailing on Lake Michigan. Sailors most in phase with working the play of gradient and thermal breezes will find the most success. Todd Basch and the Quantum Sails Great Lakes team put their heads together to create a few keynotes ahead of the Helly Hansen Sailing World Regatta Series.
- The delicate balance of gradient wind and thermals: Chicago lies on the west shore of Lake Michigan, so thermals want to come in from the east. If the gradient is south or southeast, or it dies, the breeze will go left depending on the strength of the thermal. Gradient breezes are typically S/SE.
- The dance of gradient wind and thermals can make for very different racing from morning to afternoon. Keep a weather eye out and mind the temperature forecast. On June 10, 2023, the high was 86 degrees; in 2022, it was 80; in 2021, it was 88—warm enough to significantly impact the breeze in the afternoon.
- Take a look at twist: the water temperature in June is about 10 degrees below its maximum, hovering around 50 degrees. The cool water slows the breeze and produces shear—a vertical gradient—that can be very significant, requiring a lot of twists in your sails and a different lead position from one tack to the other. Don't expect trim to be the same on each side of the boat. If the water is bumpy, the difference in "sea state" from side to side will make this more complicated to decipher.
- Chicago saw an unusual number of days with a northerly breeze through the season last year. Besides making for bumpier water because of the long fetch, the northerlies tend to be less stable and are primarily cold. Northerlies usually show up with a front or a lot of cloud cover. If things begin to clear, expect the breeze to move east.
- An offshore breeze tends to have the most pressure near shore, but it is likely to be less stable because of the uneven heating circumstances of land and buildings.
- Get out on the water an hour early to dial in for a racing day. Do a few drills to parse conditions. Sail upwind for 20 minutes, 5 minutes a tack. Do the same thing downwind. From that, you will get a baseline for the day's weather.
While you’re in town, our local Quantum team is here to help with any need — from sail repairs to tactical discussions. Good luck, and welcome to Chicago!