Praise be to Allah.
It is permissible for the one who wants to do Hajj or ‘umrah to do ghusl, put on perfume and whatever garments he wishes over the ihram garments, and to do any of the things that are prohibited when in ihram, so long as he has not formed the intention to actually begin the rituals. This is indicated by the report narrated by an-Nasaa’i from ‘Aa’ishah (may Allah be pleased with her), who said: I put perfume on the Messenger of Allah (blessings and peace of Allah be upon him) with my own hand, when he entered ihram – when he wanted to enter ihram (and before he did so) – and when he exited ihram – before he completely exited ihram (in the case of Hajj). Classed as saheeh by Shaykh al-Albaani (may Allah have mercy on him) in Saheeh Sunan an-Nasaa’i.
Al-Haafiz Ibn Hajar (may Allah have mercy on him) said:
This report is quoted as evidence that it is mustahabb (encouraged) to put on perfume when wanting to enter ihram, and that it is permissible to leave is there after entering ihram, and that it does not matter if its colour or fragrance remain; rather what is prohibited is to put it on anew when in ihram. This is the view of the majority of scholars.
End quote from Fath al-Baari (3/390)
Shaykh Ibn Baaz (may Allah have mercy on him) said: There is nothing wrong with doing ghusl, putting on the ihram garments and putting on perfume at home, because they are close to the miqaat by means of vehicles. But what is prescribed for them is not to enter ihram except at the miqaat. Ihram means forming the intention to begin the rituals. This is what ihram means. Then it is prescribed for them when forming the intention to utter the ritual intended, so one should say: “Labbayka ‘umratan (Here I am for ‘umrah)” or “Labbayka Hajjan (Here I am for Hajj).”
End quote from Majmoo‘ Fataawa Ibn Baaz (17/52)
Shaykh Ibn ‘Uthaymeen (may Allah have mercy on him) said in ash-Sharh al-Mumti‘ (7/69): The words “his intention is a condition” refer to the intention to begin the rituals, i.e., forming the intention to begin the rituals is a condition; it is essential to form the intention to begin the rituals. If a person recites the Talbiyah without intending to start the rituals, then he does not enter ihram merely by reciting the Talbiyah. If he puts on the ihram garments without intending to begin the rituals, then he has not entered ihram just by wearing the ihram garments. The Talbiyah may be recited by the pilgrim and others, and wearing the izaar and rida’ is for the pilgrim in ihram and others. End quote
Based on that, it is permissible for you to wear tailored clothes, and to wear whatever you want, to protect yourself from cold, over the ihram garments (the izar and rida’), and to do everything that the person who is not in ihram does, of the things that are prohibited whilst in ihram, even if you have done ghusl and put on the ihram garments in your home, so long as you have not formed the intention to begin the rituals. This intention – as stated above – is an essential condition, but it does not have to be done until you come in line with the miqaat. It is permissible to enter ihram before reaching the miqaat, but this is contrary to what is preferred.
And Allah knows best.