Spring (March to May) and autumn (October to November) offer the most comfortable mix of warm sunshine, hot but bearable days and ideal sea temperatures. Summer (June to August) is very hot inland but still popular for the water, while winter is mild and sunny by day with cooler evenings and slightly cooler sea, making it a favourite escape from European cold. Diving and snorkelling are good year round.
The Red Sea sun is intense, especially in summer and out on the water where the breeze hides how much you are burning. Use high-factor sunscreen, cover up, drink plenty of water, and take shade in the hottest afternoon hours to avoid heatstroke and severe sunburn.
The sea is beautiful but has real hazards: strong currents off some reefs, sharp coral, sea urchins and boat traffic. Wear reef shoes, never stand on or touch coral, follow your dive or snorkel guide, and only swim in marked or supervised areas.
Beachwear is fine at resorts and on the beach, but Hurghada is still an Egyptian town and more modest dress is respectful in El Dahar, markets and mosques. Away from the resort strip, covering shoulders and knees and keeping public affection low-key avoids unwanted attention.