Let me preface by saying that European Weather Forecasting is not something I do in my daily routine. The terrain and proximity to cool water make it more challenging than here in the Middle Atlantic. Having said that, I will take a shot. Confidence is pretty good through the first week, then gets a little shaky after you leave France.
For those with internet access, I would suggest the BBC website for weather information. Check it once every day or two for changes.
…and type in the city you need. Temperatures will be in Celsius. So a quick conversion:
London: 6-8 July
Mostly sunny days and fair nights. Afternoon highs near 80. Lows around 60. Light breezes. Very un-London-like. This looks like a gift.
Paris/Northern France: 9-11 July
Mostly sunny days and fair nights. Afternoon highs in the low-mid 80s. Lows in the lower 60s. Some cool north breezes may develop… especially Thursday, but still nice outside.
Belgium/Netherlands: 12-14 July
A mix of sun and cloudy periods. Cooler breezes from the North Sea for 13-14 (Sat-Sun). Highs Friday in the 70s. Saturday and Sunday… closer to 70. North Sea water temperature is around 60.
Western Germany: 15-19 July
Really getting shaky here…. Fair for the first couple of days (15-17), then some rainy spells and turning cooler (18-19). Highs generally in the 70s (15-17), then 60s to 70° (18-19).
Austria/Switzerland: 20-22 July
Not much skill here. But it looks fair and mild with highs in the 70s and lows in the 50s.
Have a great trip!