The answer is: yes, as long as the size, scope, and weather forecast is taken into account. Dealing with frost or freezing temperatures require extra attention to the ground surface. They also will make mortared projects incredibly difficult if not impossible. The bigger the project, the longer it may take, which means there's a greater likelihood of getting into colder temperatures which are more challenging to work with for landscape construction projects.
Low temperatures that cause heavy frost or freezing followed by thawing can result in the ground shifting. To avoid having your new patio unstable or uneven, it should be compacted frequently and checked consistently to ensure it is level. You do not want your new patio to be uneven or unstable.
If your landscape construction project includes a brick wall, patio or walkway, check the weather temperatures to ensure they're not going below 40 degrees. Mortar should be used in temps above 40 degrees for best results. If the project takes multiple days, you may be able to cover the mortared areas each night to stave off frost, so it can set properly, but this is a risky option. And once temperatures get to freezing, if your mortar has not set, it will likely fail. This will result in you having to rip out and restart your project. If your going to install a patio or other hardscape on your own, you may want to err on the side of caution and wait until the spring to do it. That way, if you'r running into issues or just taking than longer than you expected, you don't get to those too cold temps that thwart your efforts all together. Or you can consider using paver stones or other materials that don't require mortar. If you're hiring a professional landscaper, they should be able to complete the project pretty quickly without issue.
Essentially, early to mid fall is a great time to install a patio or other hardscape because:
1. You avoid having construction interfere with your summer outdoors
2. You can complete your big landscape project in time to weather the New England winter and
3. You get an early start to enjoying your outdoor space next spring, when your itching to get outside again.
Nice and Green Landscape or another professional landscaping contractor can asses your property and landscape construction plan to determine whether or not a hardscape installation this fall is a good idea.