Plants are sensible to changes in light, food and watering methods. This is why, when watering, you need to pay attention to the water temperature.
It is best to use water at room temperature.
Using cold water doesn’t necessarily kill the plant but it can stop it from growing and blooming. This happens because the plant enters a state called winter mode.
Hot water damages the plant, making it wilt even if it is blooming healthy. Do not use hot water under any circumstance.
Exceptions to the rule
Plants that grow outdoors are used to varying temperatures. Vegetables and other plants won’t be damaged in anyway if you use colder or hotter water than normal.
Using rainwater to irrigate your plants is a very good idea because rainwater contains more minerals and nutrients. Storing and using the rainwater is an effective irrigation method.