Could you check my corrections?

This is a composition of one of my students:

"The best time to
visit in Moscow is the summer. There is a lot of historical sites,
museums and
excellent park. Moscow is notably beautiful in the
summer. Fountains, grass-plats with diverscolored
flowers decorate
city. From June to mid-September, Moscow having a low population
rate, because
many townspeople are away on vacation. Then weather is
warm and no rainy. Moscow is valuable
 city and prices are high all
(the) year round."

I've made some corrections (in italics): 

"The best time to visit Moscow is in the summer. There are a lot of historical sites, museums and
excellent parks. Moscow is notably beautiful in the summer. Fountains, lawns with many-coloured
flowers decorate the city. From June to mid-September, there is a decrease in the population of
Moscow, because many citizens are away on holiday. Then the weather is warm and not rainy.
Moscow is an expensive city so prices are high all the year round."


Could you check it, please?

Some comments:
The student tends to use too difficult and rare words, so I've changed some to more common.
This composition is supposed to be in BrE. 
If some of my corrections are unnecessary, please tell me.
The student is at pre-intermediate level of English.