Israel
In general, the weather in Israel during the summer is quite hot, averaging in 90s (°F), although the climate varies significantly in different parts of the country. It is very dry in the desert, with intense heat in the daytime and cool & windy nights. Along the coast near Tel Aviv, it is much more humid. In the mountains up north and in the Jerusalem area both the temperature and humidity are more moderate, although it is still very warm. The good news is that you never have to worry about rain, so you can leave the umbrella at home. Because of the extremely strong sun, you will usually be required to wear a hat and a shirt that covers your shoulders whenever you are outside.
Europe
Spain & Italy: Average temperatures in June and July are in the mid 70s (°F), although it may go down into the 60s at certain times of day in some locations. Rain is a possibility, so bring a jacket that can handle it, preferably with a hood.
Bulgaria, Western & Central Europe: Average temperatures in June and July are in the low-mid 60s (°F), although it is likely to go up into the 70s or even down into the 50s at different times of day in some locations. Rain is a definite possibility, so bring a jacket that can handle it, preferably with a hood.
Costa Rica
Average temperatures in Costa Rica in June and July are in the low-mid 70s (°F), although it could go up into the 80s or down into the 60s at different times of day in some locations. You will be traveling through the rainforests, so rain is a definite possibility! Bring a jacket that can handle it, preferably with a hood.
Western USA
In general, the weather in the Southwest during the summer can be quite hot, although the climate varies significantly in different parts of the country. It is very dry in the desert, with intense heat in the daytime and cool & windy nights. Along the coast near San Francisco and Los Angeles, it is much more humid. In the mountains up north both the temperature and humidity are more moderate, although it is still very warm. Because of the extremely strong sun, you will usually be required to wear a hat and a shirt that covers your shoulders whenever you are outside.
South Africa
Average temperatures in South Africa in July are in the 50's and 60's (°F) although it is likely to go down into the 40s at different times of day in some locations. Rain is a definite possibility, so bring a jacket that can handle it, preferably with a hood.