This mod has a lot of potential, but at the moment, there is no way of dealing with heat.
Spawning at one of the warm biomes means you will deplete your entire saturation in just a couple minutes.
For cold, you have n+1 options.

Some suggestion from a person who lives in a warm country:

New Items:

• Ice Cube (Imagine a nugget, but for Ice Blocks)
• Cold Water Bottle (Water Bottle + Ice Cube)
• Fabric (9 Strings)
• Cold Juice (Cold Water Bottle + Melons/Apples/Sweet berry/ Chorus fruit)
• Milkshake (Milk + Sugar + Ice Cube)
• Ice Cream (Milk + Sugar + Ice Cube + Melons/Apples/Sweet berry/ Chorus fruit optional)
• Popsicle (Stick + Ice Cube + Melons/Apples/Sweet berry/ Chorus fruit)

If possible, all would transform after a while depending on the temperature.
Ice Cube → vanishes
Cold Water → Turns into [Water Bottle]
Popsicle → Turns into [Stick]
Cold Juice, Milkshake, Ice Cream → Turns into Suspicious Blend similar to [Suspicious Stew]

But this would unbalance things. So you could have another item:

• Insulated Bottle (1R → 3 Iron Nuggets | 2R → 2 Papers + Empty Bottle + 2 Papers | 3R → 3 Iron Nuggets)
  (Very common insulating method called "Double Wall")

New Block:

• Fridge
  (Consumes [Redstone Dust]/[Redstone Block] to work)
  Turns [Water Bucket] → [Ice Block] + [Empty Water Bucket]
  Turns [Water Bottle] → [Cold Water Bottle]

New Armor Set:
(Reduces heat + Increase Cold / made out of: Fabric)

• Hat (+ Leather)
• Light/Loose Shirt
• Light/Loose Pants
• Sandals (+ Leather)

Added an Ice Pack with faf6c3c
You have great ideas here, thanks :)

Is there any way to configure the ice pack so it lasts longer ?

Because when i go to the nether it lasts literally like 30 seconds or so, which makes it completely useless

No this is a set value which can not get changed.
Added a new armor set for keeping you cool in hot environments + the ability to add ice to armor.