Yes, but prioritize loose-cut jeans over tight skinny jeans. In extreme heat, you will likely find denim too heavy and uncomfortable.

Do I need to wear an abaya?

Unless you are in a country with a strict legal dress code like Saudi Arabia or Iran (and even there, rules have relaxed for tourists), you are not required to wear an abaya. Dressing modestly in your own clothes is perfectly acceptable.

Is it different in major cities versus rural areas?

Yes. Cities like Dubai or Doha are very cosmopolitan and you will see a wide variety of dress, but you should still maintain a baseline of modesty to avoid unwanted attention and show respect.

How to dress appropriately in conservative Middle Eastern countries

Dress modestly by ensuring your shoulders and knees are covered at all times in public. For women, keep a lightweight scarf handy to cover your hair when entering religious sites or traditional areas, and choose loose-fitting fabrics to manage the heat.

Prioritize loose-fitting layers. Avoid tight clothing. Opt for breathable fabrics like linen or light cotton. Loose silhouettes keep you cool and respect local customs regarding body shape.
Cover the 'modesty zones'. Regardless of gender, your torso should be covered from the neck to below the knee. Avoid tank tops, sleeveless shirts, and shorts that end above the knee.
Carry a versatile scarf. Women should always carry a pashmina or large cotton scarf. You will need it to cover your head in mosques and to provide extra coverage if you feel underdressed in a specific setting.
Choose closed-toe footwear. While sandals are acceptable in many urban areas, closed-toe shoes are safer for navigating uneven streets and are more respectful when visiting formal government buildings or religious sites.
Check local norms for specific sites. Before visiting a specific mosque or tomb, check the signage. Some places provide abayas (long cloaks) for rent, but bringing your own long, loose dress or trousers is always more convenient.

Can I wear jeans?: Yes, but prioritize loose-cut jeans over tight skinny jeans. In extreme heat, you will likely find denim too heavy and uncomfortable.
Do I need to wear an abaya?: Unless you are in a country with a strict legal dress code like Saudi Arabia or Iran (and even there, rules have relaxed for tourists), you are not required to wear an abaya. Dressing modestly in your own clothes is perfectly acceptable.
Is it different in major cities versus rural areas?: Yes. Cities like Dubai or Doha are very cosmopolitan and you will see a wide variety of dress, but you should still maintain a baseline of modesty to avoid unwanted attention and show respect.