Weather forecast builder for the Sultan's Trail: Sofia → Istanbul

The Sultan’s Trail from Sofia to Istanbul crosses Bulgaria’s cooler interior, then descends through open Thracian plains into Turkey’s warmer, more humid lowlands near the Marmara. April, September, and October align with the more settled walking windows outlined for this direction, balancing warming spring stages with easing heat toward the Marmara shore. These periods typically bring milder temperatures, good daylight, and fewer abrupt shifts than midwinter’s cold mix or high summer’s intense heat along exposed sections.

• Winter: Cold around Sofia with snow or slush possible; milder toward Istanbul, frequent rain, variable skies, occasional sunny breaks.
• Spring: Changeable days with sun and showers; occasional lingering snow early; warming toward Istanbul; tracks sometimes muddy after passing rain.
• Summer: Long days with generally warm to hot conditions; exposed plains feel intense; intermittent showers or storms, trending drier toward Turkey.
• Autumn: More settled early, with warm days and cooler nights; periodic rain increases later; alternating showers and sun near the Marmara.