美国预测 2026 年赤道太平洋出现 El Niño 的机率为 80%，但 3 月至 4 月的「spring barrier」会在北半球由冬转夏时削弱预报技巧，因此目前仍有 20% 的机率不会成真。Michelle L’Heureux 强调，近期讯号异常强，但现在判定是否会出现所谓 super El Niño 仍然过早。

这种季节性不确定性曾造成明显误判。2012 年与 2014 年，偏乐观的 El Niño 预测都落空；2012 年 Colorado State University 在 4 月仅预测 10 个大西洋命名风暴，但最终数量几乎翻倍，且包含重创美国东北部、至少造成 147 人死亡的 Super Storm Sandy。这显示早期 ENSO 预测错误会连带影响能源、农业与飓风风险判读。

目前支持 El Niño 的主要证据是海洋增暖，不仅海表升温，次表层海洋也较暖；但另一个关键条件，即赤道太平洋地表风持续减弱，尚未完全形成。现有风力变化或许已足以终结 La Niña，但是否会在 2026 年稍后至 2027 年初转入 El Niño、以及强度多大，仍未确定；Michelle L’Heureux 并指出，今年冬季 La Niña 回归的机率仍有 1%。

The US assigns an 80% chance that El Nino will emerge in the equatorial Pacific in 2026, but the March-April spring barrier reduces forecast skill as the Northern Hemisphere shifts from winter to summer, leaving a 20% chance that it will not form. Michelle L’Heureux said the recent signal is unusually strong, yet it is still too early to confirm a so-called super El Nino.

This seasonal uncertainty has produced major forecasting errors before. In 2012 and 2014, optimistic El Nino calls failed; in April 2012, Colorado State University projected only 10 named Atlantic storms, but the final count was nearly double and included Super Storm Sandy, which devastated the US Northeast and killed at least 147 people. The case shows that early ENSO errors can distort energy, agriculture, and hurricane-risk expectations.

The main evidence favoring El Nino now is ocean warming: sea surfaces are warmer and subsurface waters are also warmer. However, the other critical condition, sustained weakening of surface winds along the equatorial Pacific, has not fully developed. Current wind changes may already be enough to end La Nina, but whether the climate flips into El Nino later in 2026 or early 2027, and how strong it becomes, remains uncertain; Michelle L’Heureux added that there is still a 1% chance of La Nina returning this winter.