There are three times during which no fard or wajib salaat can be performed:
From sunrise to after it has risen,
When the sun is at its zenith at midday until it shifts from its position.
When the sun turns yellow until it sets.
The exception is if a janaaza becomes ready so it should be prayed or sajdah tilawat may be done at these times.
Likewise it is valid although makrooh to perform the ASR of the same day after the sun has turned yellow.
In the prohibited times all nafl salaats are makrooh tahrimi even though they have some cause (i.e. you took an oath to perform salaat or they became necessary because of performing tawaaf.
TIMES WHEN NAFL SALAAT IS MAKROOH
After the true dawn (except the two sunnat of fajr)
After fajr (until ten minutes after sunrise)
After asr (till sunset)
Before maghrib salaat
When the imam climbs on the mimbar for the khutbah and until he completes the salaat
When the iqamat is called
Before eid salaat even at home
After the eid salaat in the masjid or eidgah (it’s ok to pray at home at this time)
Between the combined salaats on the plains of Arafat and muzdalifah during hajj.
When the time remaining for performing the fard salaat is very little
When one needs to relieve himself