We suggest you to bring the following clothing and hiking gear during your summer hiking in Nepal.

Clothing

Wool, part wool or synthetic underwear 
Wool socks/stockings
Wind jacket/anorak or all-weather jacket
Mountain trousers
Shirt or light sweater of wool or fleece 
Boots
Rucksack

In pack or pockets

Rain jacket (if your jacket isn't all-weather)
Rain trousers (if your trousers aren't all-weather)
Cap/hat
Scarf/neckband 
Gloves/mittens
Sweater/jacket, wool or fleece
Wool, part wool or synthetic long underwear 
Shorts
T-shirt
Sleeping bag/sleeping liner
First aid kit
Indoor footwear
Extra underwear (trousers, shirt, socks)
Extra indoor trousers (optional)

Toiletries
Towel
Toilet paper
Suntan cream
Sunglasses
Insect repellent 
Map and compass
Map case (with pencil and paper)
Knife
Headlamp/flashlight
Boot waterproofing
Lunch packet 
Thermos or water bottle
Emergency rations 
Money
Keys (cabins, car, home etc.)
DNT membership card

Total weight: 7 - 12 kg.

For Tent camping you also need 

Sleeping bag
Sleeping pad
Cook set and fuel
Food
Cup
Plate and cutlery
Tent
You can leave out a thermos

Total weight can easily be 15 - 20 kg for tenting

Other Useful gear

Binoculars
Camera
"Trail photos I Norge" guidebook
Transport schedules
Glasses
Medicines
Tickets
GPS
Book(s)

Candle 
Firestarter paper 
multi-purpose tool
Sitting pad

In forests you can get along with less gear and need not have the The quality needed  for mountain tours. The same applies to shelters areas along  the coast.

Spring and autumn can have winter weather in the mountains, so extra warm clothing is essential.

Pack light and don't take too much!