This is the outlook for the next four weeks using the JMA model issued from the Japanese Met Agency. I have added the 3 images together rotated them and added a red line so you can see the UK. Blue colours are low pressure area. Oranges are high pressure area.
Week 1. 28th June to 4th July.
Low pressure system north of Scotland stretches eastwards into Europe. This brings a cool, unsettled start to this period becoming drier from the weekend onwards. Temperatures are a little below what you would expect for the end of June early July.
Week 2. 5th July to 11th.
Low pressure is situated over the UK and the North Atlantic. This period will see above average rainfall and temperatures below average for July.
Week 3. 12th July to 25th.
At some point during this two week period high pressure will start to extend from Southern parts of the UK stretching northwards into the Midlands. This will start to bring drier, warmer conditions.