When travelling, we recommend packing in preparation to handle common weather conditions. The rainfall in Gatwick is typically similar to Fresno. We can gather that this will continue over the next 12 days.
You can imagine temperatures to be in the 37 °C range in July. The weather in Fresno is generally hotter than Gatwick's. As flight availability is subject to become more limited as peak season approaches it is ideal to book in a timely manner.