2027 Marathon PRs May Be Affected by Strong El Niño

A record-strength El Niño forming in the Pacific Ocean could make 2027 a tough year for marathon personal records, according to Marathon Handbook. The event is expected to be one of the strongest ever recorded, leading to higher temperatures.

Climate scientists predict 2027 will be the warmest year on record, surpassing 2024. This heat could impact marathon times, with elite runners performing best at around 12 C and slower times at higher temperatures. Read more culture coverage.

Research shows that every extra degree Celsius above 15 C costs runners an average of 0.56 minutes. Marathon organizers are already adjusting race dates and times to mitigate the heat, but runners must also prepare for warmer conditions. Related: Chelsea Clinton's Improved Marathon Pacing.

This original Runner World brief is based on reporting from Marathon Handbook. Visit the source for its complete reporting, context and any later corrections.

Questions about this report

What should runners know about 2027 Marathon PRs May Be Affected by Strong El Niño?

A powerful El Niño event could make 2027 a challenging year for marathon personal records. A record-strength El Niño forming in the Pacific Ocean could make 2027 a tough year for marathon personal records, according to Marathon Handbook. The event is expected to be one of the strongest ever recorded, leading to higher temperatures.

When did Runner World publish this culture brief?

Runner World published this brief on October 14, 2026. The underlying Marathon Handbook report was dated October 14, 2026.

Where can readers find the complete original report?

This summary is based on reporting from Marathon Handbook. The attributed source link in the article leads to the publisher’s complete report.

Questions about this report

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