When travelling, it's generally smart to pack in preparation for rain or any other conditions that may arise. The rainfall in Johannesburg is roughly greater than that of Ufa. You can assume this to be the case over the next 19 days.
You can imagine temperatures to be in the 26 °C range in July. The weather in Ufa is generally hotter than Johannesburg's. As flight availability is subject to become more limited as peak season approaches it is ideal to book in a timely manner.