As good a time as any and better than most.
Your hydrometer should have the temperature at which it is calibrated written on it, if not assume that it's 20oC, any hotter or colder you need to apply a correction and as that's close to most pitching temperatures, yes its a good time.
As you are fairly new I will state the obvious, don't take offence if you already know all this, its likely that others wont.
Don't throw the hydrometer in and try to read it.
Take a sample from the tap, run off a little 50mL give or take (what is in the tap body may not be the same as the rest of the beer) then fill the hydrometer jar.
Allow the hydrometer to sit in the wort for 10 minutes or so (lets the temperatures all equilibrate), spin it to knock off any bubbles and make sure it is floating freely before reading (not sticking to the sided).
Don't pour the wort in the test jar back into the fermenter, almost guarantees an infection, I usually (well always) taste it.
All really basics, but good brewing practice is largely about doing basics well and consistently (and cleaning and cleaning and...)
Mark