The weather here in Sinai can be separated into two categories:

• The normal conditions: sunshine, zero clouds, clear to hazy with northerly wind medium to strong along the coast, created by thermal conditions in both Sinai and the Arab Peninsula

• Abnormal conditions: in case South Sinai or the Arab  falls into the zone of influence of regional or over-regional meteorological phenomena (big low pressure areas, storms, bad weather fronts) that can disturb the local weather pattern and stop the thermal development, leading to either zero wind, heatwaves or south wind conditions with thunderstorms

Abnormal conditions is what you need to watch out for, - if you can see Castellanus clouds forming in the morning it is a clear sign (as anywhere in the world) that thunderstorms might occur before the evening.