Discs are typically weighed in grams and according to the PDGA technical standards, a disc must not exceed 200 grams. Most discs tend to weigh between 160-180g but there are some that weigh more or less depending on what their intended use is. Lighter discs take less effort to throw than heavy discs which allows slower arms to get them up to speed properly and get a full flight out of their disc. However, light weight discs are also affected by wind more, so heavier discs tend to flight more consistent and aren't affected by the wind as much.
Types of Discs
When you are trying to figure out what weight to get your putter in, there is really one main thing that you are looking for... wind resistance! Players tend to prefer heavier putters (172g+) since they are much better at fighting the wind. Since a putter is thrown softly, this gives the wind more opportunity to affect the flight of the disc.
For putters, we almost always recommend heavier weights. There is some advantage to a lightweight putter, but the pros don't outweigh the cons.
When it comes to lightweight discs, we recommend that you don't go too light with your mid-ranges. Sure, you can get a bit more distance with a lighter disc, but you already have your drivers for when you need distance.
Your mid-ranges are going to be more for shorter, accurate throws. You don't need big distance with these... you need consistency! We recommend keeping your mid-ranges somewhere close to 170g+ if possible.
When selecting the best weight for a disc golf driver, the most common factors to consider are distance and wind resistance. When it comes to drivers, the pros of a sub 160g driver typically don't outweigh the cons.
For carrying lightweight drivers, we recommend that you bag something neutral/understable for calm days or tailwinds and something overstable to help you battle the wind! Something in the 160-169g range is typically good
What to throw
During windy conditions
When throwing into a headwind
When you want consistency over precision
When you want extra stabilty
In warmer weather
When throwing a skip shot
When putting and concerned about wind
When extra distance is needed
When throwing into a tailwind
When you want precision over consistency
When learning how to throw
In colder weather
When you want a softer landing