When travelling, we recommend packing in preparation to handle common weather conditions. The rainfall in Saltillo is typically less than Hong Kong International. We can gather that this will continue over the next 4 days.
You can imagine temperatures to be in the 31 °C range in July. The weather in Hong Kong International is generally hotter than Saltillo's. As flight availability is subject to become more limited as peak season approaches it is ideal to book in a timely manner.