The start of June 2016 will be above average in temperatures, with Friday June 3rd being the hottest day in the beginning of June. A ridge of high pressure will park over the Western United States, bringing a large area of sinking air into the California area. Temperatures during the first week of June 2016 will be way above average, with widespread inland 100 to 110 degree temperatures, with hotter temperatures in the lower deserts of Southern California.
Toward the second week to the middle of the month, cooler temperatures will come in to save those who do not like heatwave level temperatures as a trough of low pressure breaks the ridge down from the west. This also will reinforce the June Gloom pattern across metro Southern California.
The large trough will breakdown yet again and a very strong ridge would then develop over the Western United States again .. and possibly be stronger than the one in the beginning of the month. The first day of summer will feel like Summer with heatwave level temperatures across the Western United States.