Local Knowledgepublished on
By Bill Fastiggi, Vermont Sailing Partners
Many folks are wondering what the weather is going to be like in Vermont in September. Depending on the weather systems, we could see air temperatures from anywhere between 60 and 75 degrees during the day. If we have a cold front, it could get down into the low 50’s at night. Most likely though, the air temperature will be a comfortable 65 degrees.
The water temperature on Lake Champlain in September will be about 70 degrees. So you will definitely want a spray top at a minimum, but if we have a cold front come through and it is windy, you will definitely want full sailing gear, perhaps even a drysuit if you are in the front of the boat. Be prepared for anything!
There will be two sailing areas in Malletts Bay. The primary sailing area will be the “Outer Bay”. The secondary racing area will be the “Inner Bay”.
The Outer Bay is a nearly circular bay 4 ½ miles wide, that is almost completely separated from Lake Champlain by an auto causeway to the north, and a railroad fill to the west. With an average water depth of 70 feet, this configuration provides an excellent body of water for racing with “wind appropriate” wave heights and minimal powerboat traffic. It will take 35 minutes to 1 hour to sail out to the course area, depending on the wind strength and direction.
The Inner Bay is also a circular bay, but is only a little over 1.3 miles across. There is a large peninsula “Coates Island” that extends into the bay and can effect the wind on that part of the bay. The “Inner Bay” course area will feature very flat water, and shifty sailing conditions. We would only use this venue if the “Outer Bay” is not sailable because of extremely high winds.
The wind speed in mid-September on Lake Champlain averages about 10 knots. Winds generally blow from the south-southwest 46% of the time. The next most frequent wind direction is North-Northwest at 22% of the time. Westerly winds are a distant third, with Easterly winds almost never occurring. Winds are calm less than 15% of the time. As usual anything can happen when you host a regatta. We have sailed two straight days in an easterly wind.
Typically, winds will be out of the south ranging anywhere between 7 and 20 knots. On warmer days, winds may shift to the west bringing late afternoon thunderstorms across the lake from New York, although thunderstorms are unlikely this late in the season.
In the Outer Bay, the “typical” day will have us sailing in a southerly breeze, that starts out at around 4-5 knots and will build to about 8 knots by late morning. Expect the breeze to build to about 12 knots and die back down late in the day. The breeze will be fairly steady with small 5-15 degree shifts, but be prepared for the occasional larger, more permanent shift.
In the inner bay, the southerly will be very puffy and shifty, but the sailing will be fun and fair. You’ll need to pay close attention to the shifts.
Shifty, puffy Northwest winds accompany cold fronts which typically last for three days. Day one will be strong winds most of the day, but getting lighter late in the day. Day two will start out moderately, but will be very light by mid afternoon, and there will be no sailing or possibly a light afternoon southerly wind on day three.
West winds are usually very unstable and occur very infrequently, but when they do anything can happen. Hopefully, we will not see winds out of the east.
There is no thermal or sea breeze, and the sailing conditions will be dependant upon the local weather systems. Overall you should expect a variety of conditions for the regatta.