I was wondering whether anyone could tell me if these words are completely interchangable all situations. If not, how am I to discern which to use?
凉 means cold(冷), but not that cold. For example:
"我们快吃吧，食物快凉了" - Let's eat, the food is getting cold.
"今天的天气真凉快" - The weather today is good.
冷 means cold.
"我好冷啊" - I'm feeling cold.
"天气真冷" - The weather is cold.
"一杯冷水" - A cup of cold water.
冻 means cold/freeze too, but freezing cold or something frozen.
"冻死我啦" - So freezing cold.
"冻疮" - Frostbite "冻肉" - Frozen meat.
"果冻" - Pudding.
冰 means ice, very cold or icy cold.
"冰块" - Ice cube.
"冰点" - Freezing point (of a substance).
"冰箱" - Refrigerator/freezer.
If you want me to arrange those words according to the temperature, I'd say 凉 -> 冷 -> 冻/冰.
I hope this helps you. If you have any questions, just comment below.
凉 is often objective,well 冷 is often subjective,we usually use "冷" to express our feelings,but it can be objective sometimes,like"冷水".But "冷" is more severe than "凉","冷" often means it's too cold that you can't stand it,well "凉" means it's cold but it's OK.For example,in summer it's very hot,we say we want things that are “凉”,not 冷，to cool us down. 冻 is a adj,it means frozen.Well 冰 is used as a noun more often which means ice.冰 can be a adj too,but it means "similar to ice in shape" or just cold(very close to 冷),not frozen. Examples:冰糖 means a kind of solid sugar which is very similar to ice in shape.冰水 means ice water,no huge difference to 冷水.
凉 adj cold
冷 adj cold
冻 verb freeze
冰 noun Ice
From these 4 characters, we can also make the following phrases,
冻冰 verb freeze 河冻冰了。 river gets frozen. 冷冻 adj.frozen; 冷冻食品，frozen food Verb freeze 我把虾冷冻了。，I freeze the shrimp. 冰冷 adj freezing e.g.冰冷的面庞. Freezing face 冰凉 adj icy cold e.g.冰凉的水. Icy cold water
凉and冷 are both adj, very similar when it's describing temperature. But, 凉 is a little bit less cold than 冷。 we can say winter is 冷， late autumn is 凉。for the most of cases, they can be substituted.
Hope the bellow example will help you sense the difference of these 4.
It's getting cold, cold water freezes into ice.
When ice meets cold water, it will defreeze.