No-one can guarantee the weather, but we have been living in this region since 1985 and this seems to us a fair indication of what you can reasonably expect from the weather:
With an annual average of 2000 hours of sunshine, the Midi-Pyrenées region is one of the sunniest in France. Temperatures in excess of 25°C [77°F] are recorded for 60 to 80 days per year over most of the region, rivalling those of the Mediterranean strip and the Rhone valley. Spring, which comes very early, already has a summer feel – the perfect time for hiking and walking. Between early April and late June, maximum temperatures average 16 to 24°C [61 to 75°F]. In July and August, hot, intense sunshine prevails. Average minimum temperatures, already high, now range between 13 and 15°C [55 and 59°F]. In the daytime, average temperatures reach a maximum of 26 to 28°C [79 to 82°F]. This said, the air becomes pleasantly cooler at night. Autumn often has the mildness of an Indian summer, noteworthy for wonderful days of ultramarine skies. In the beautiful light of September, maximum temperatures range between 21 and 25°C [70 and 77°F]. They remain very clement in October with average maximum temperatures of 16 to 19°C [61 to 66°F]. Perfect for treating oneself to a quiet break whilst others are working! Source: Regional tourist authority, based on information provided by Météo France