June though its mid-summer is often not as searing as May, though that’s often because the rise in humidity also drops the temperature. This year June is the month of Ramadhan when many hotels offer special meals after dusk.
Indoor bowling is a great activity during Ramadhan as its in air-conditioned comfort and is great with family and friends. Fun Zone in Al Qurum has a number of lanes and also has a number of snack outlets in the same location.
Ras Al Jinz is distantly cooler than Muscat and June is peak nesting time for the Green Turtles. The evening and dawn watching at this time of year are usually very rewarding. To watch at dawn means an early start though it does have the advantage that the authorities allow the use of a camera.
From Muscat a flight down to Salalah will bring you into much cooler weather and you should expect the day time temperature to be below 30c. There is a good choice of flights and Salalah Airport has a number of car hire companies in the airport. There are several hotels along the sea front between Mirbat and Salalah town with the drive to the Marriott less than an hour and the Hilton less than 15mins.
In Salalah a visit to Al Balid, on the coast in the centre of the town, offers a very interesting Museum along with a fascinating outdoor archaeological park. The park is within the walls of a medieval town on the sea front that was visited by Zheng He the Chinese admiral between 1405 and 1433. Though it’s a great visit at any time, late afternoons and evenings are of course cooler. The museum itself is a traditional one with objects in display cases, no interactive displays. Check out the Frankincense trees in the area south of the car park.
Al Balid’s companion site is Samharam 30kms east of Salalah which was famed as a port for the trade in Frankincense. As with Al Balid this is ideal as a late afternoon visit, though as it’s a good birdwatching location an arrival just after opening is also good. The site contains the ancient fortified town that flourished as a trading port between 300BC & 400AD. Below the walls is a vast natural creek, that is wonderful for birdwatching.
In June the monsoon season, called the Khareef in Oman, is strengthen and will affect the mountains surrounding Salalah. The most accessible area is Wadi Darbat, north of Samharam. Here in a beautiful valley trees cascade down to the valley floor and herds of camels, cows and goats create a bucolic atmosphere. Later in the month the seasonal lakes should be full and these attract wading birds such as heron and egrets. Unlike the other attractions Wadi Darbat has no entrance charge.
More details of these in the Bradt Guide to Oman