A new scientific study presented at the European Geosciences Union (EGU) General Assembly this week has confirmed what many pilgrims experienced first-hand: during the 2024 Hajj, heat and humidity conditions exceeded the physiological limits of human survivability for approximately four consecutive hours - making unshaded outdoor exposure potentially fatal even for young, healthy adults.

What the Research Found

The study, led by Atta Ullah from Weather and Climate Services in Islamabad and Climate Analytics in Berlin, analysed the precise conditions during the 2024 Hajj season. The critical finding: on June 17, 2024, the combined effect of heat and humidity breached the threshold beyond which the human body cannot maintain a safe core temperature through sweating alone.

During this four-hour window, no amount of water consumption or rest could compensate for the body's inability to cool itself naturally. Without external cooling - air conditioning, misting systems, or shaded shelter - prolonged exposure during this period was life-threatening regardless of age or fitness.

At least 1,301 pilgrims died during the 2024 Hajj, with the majority of deaths attributed to heat-related causes. Many were performing Hajj without official permits and therefore lacked access to air-conditioned tents, organised shade, and medical support.

The Day of Arafah: Highest Risk

The researchers identified the Day of Arafah as the single most dangerous period. Pilgrims spend the entire afternoon (approximately 5-6 hours) on the open plain of Arafat, often with minimal shade infrastructure. This is the pillar of Hajj - the one ritual that cannot be skipped or shortened.

The 2024 heat crisis has driven significant infrastructure investment for 2026. Saudi Arabia has expanded shading at Arafat to five times its previous coverage, with 272,000 square metres of canopies, 36 misting fans, and 107 misting columns now in place.

What This Means for Hajj 2026

The good news is that Hajj 2026 falls in late May rather than mid-June, bringing significantly cooler conditions. The Islamic lunar calendar has shifted Hajj into spring months for the next 16 years, with temperatures expected to be 8-10 degrees lower than the 2024 peak.

However, May temperatures in Makkah can still reach 40-42 degrees Celsius - hot enough to cause heat exhaustion, especially during extended outdoor periods like Arafah and the walk from Muzdalifah to Mina.

The Long-Term Warning

The study's most sobering finding concerns the future. While the next 20-30 years offer respite as Hajj moves through cooler seasons, around 2050 the pilgrimage will shift back into the hottest months. If global temperatures continue to rise, the researchers warn that Hajj could face conditions even more extreme than 2024.

The conclusion is stark: "Adaptation measures can reduce danger but cannot eliminate threats if global warming continues. Climate mitigation is essential to preserve Hajj's traditional practice and protect pilgrim health."

What Pilgrims Should Do Now

For Hajj 2026, the immediate heat risk is lower than recent years, but not eliminated. Every pilgrim should:

  • Carry and use an umbrella at all times outdoors - especially during the Day of Arafah
  • Drink water continuously - at least one litre per hour during outdoor exposure
  • Seek the shaded canopy areas at Arafat during the hottest afternoon hours
  • Carry ORS sachets (oral rehydration salts) - more effective than water alone at preventing dehydration
  • Know the signs of heatstroke - confusion, hot dry skin, rapid pulse, loss of consciousness. This is a medical emergency requiring immediate help.
  • Never perform Hajj without a permit - the 2024 deaths were overwhelmingly among unregistered pilgrims who lacked access to organised shade, cooling, and medical support