Marsa Matruh is first and foremost a summer resort. June to September is the high season, when Egyptian families pour in from Cairo and Alexandria to escape the heat of the Nile Delta. The beaches are crowded, accommodation is expensive, and the town is lively. The sea temperature is warm — around 26–28°C — and the water is at its calmest. Book accommodation well in advance for July and August.
May and October are the sweet spots: the sea is still warm enough to swim, the crowds have thinned, and prices drop sharply. Spring can bring the occasional khamsin — a hot, dusty desert wind off the Sahara — but these are short-lived. Autumn is generally more settled.
Winter (November to March) is very quiet. Most hotels and restaurants close or operate at skeleton capacity. The weather is mild by European standards — daytime temperatures of 15–20°C — but the wind off the sea can be sharp. The beaches are empty, which makes for fine walking, and the war sites and museums are uncrowded.