RONI (operational index) vs. NOAA strength bands
RONI (operational index) data as of MJJ 2026 · Source: NOAA CPC
View as a table
| Current value | +0.65°C |
|---|---|
| Classification | Weak El Nino |
| Very strong El Nino | ≥ 2.0°C |
| Strong El Nino | ≥ 1.5°C |
| Moderate El Nino | ≥ 1.0°C |
| Weak El Nino | ≥ 0.5°C |
| Neutral | -0.5°C to 0.5°C |
| Weak La Nina | ≤ -0.5°C |
| Moderate La Nina | ≤ -1.0°C |
| Strong La Nina | ≤ -1.5°C |
| Very strong La Nina | ≤ -2.0°C |
ONI (shown alongside RONI for continuity)
+1.20°C
El Nino · moderate
ONI data as of MJJ 2026 · Source: NOAA CPC
Wondering why these two numbers differ? Read ONI vs RONI.
Weekly Nino 3.4 anomaly, last 18 months
Weekly SST data as of 2026-07-13 · Source: NOAA CPC
View as a table
| Week of | Anomaly (°C) |
|---|---|
| 2025-01-20 | 0.10 |
| 2025-01-27 | 0.10 |
| 2025-02-03 | 0.10 |
| 2025-02-10 | 0.20 |
| 2025-02-17 | 0.10 |
| 2025-02-24 | 0.10 |
| 2025-03-03 | 0.20 |
| 2025-03-10 | 0.20 |
| 2025-03-17 | 0.10 |
| 2025-03-24 | 0.20 |
| 2025-03-31 | 0.20 |
| 2025-04-07 | 0.20 |
| 2025-04-14 | 0.10 |
| 2025-04-21 | 0.20 |
| 2025-04-28 | 0.20 |
| 2025-05-05 | 0.20 |
| 2025-05-12 | 0.20 |
| 2025-05-19 | 0.20 |
| 2025-05-26 | 0.20 |
| 2025-06-02 | 0.20 |
| 2025-06-09 | 0.20 |
| 2025-06-16 | 0.30 |
| 2025-06-23 | 0.20 |
| 2025-06-30 | 0.20 |
| 2025-07-07 | 0.30 |
| 2025-07-14 | 0.30 |
| 2025-07-21 | 0.20 |
| 2025-07-28 | 0.20 |
| 2025-08-04 | 0.30 |
| 2025-08-11 | 0.30 |
| 2025-08-18 | 0.20 |
| 2025-08-25 | 0.30 |
| 2025-09-01 | 0.30 |
| 2025-09-08 | 0.30 |
| 2025-09-15 | 0.30 |
| 2025-09-22 | 0.30 |
| 2025-09-29 | 0.40 |
| 2025-10-06 | 0.30 |
| 2025-10-13 | 0.30 |
| 2025-10-20 | 0.40 |
| 2025-10-27 | 0.40 |
| 2025-11-03 | 0.30 |
| 2025-11-10 | 0.30 |
| 2025-11-17 | 0.40 |
| 2025-11-24 | 0.40 |
| 2025-12-01 | 0.40 |
| 2025-12-08 | 0.40 |
| 2025-12-15 | 0.50 |
| 2025-12-22 | 0.50 |
| 2025-12-29 | 0.50 |
| 2026-01-05 | 0.60 |
| 2026-01-12 | 0.70 |
| 2026-01-19 | 0.60 |
| 2026-01-26 | 0.60 |
| 2026-02-02 | 0.80 |
| 2026-02-09 | 0.80 |
| 2026-02-16 | 0.70 |
| 2026-02-23 | 0.80 |
| 2026-03-02 | 0.90 |
| 2026-03-09 | 0.90 |
| 2026-03-16 | 0.90 |
| 2026-03-23 | 1.00 |
| 2026-03-30 | 1.10 |
| 2026-04-06 | 1.10 |
| 2026-04-13 | 1.10 |
| 2026-04-20 | 1.30 |
| 2026-04-27 | 1.30 |
| 2026-05-04 | 1.30 |
| 2026-05-11 | 1.30 |
| 2026-05-18 | 1.50 |
| 2026-05-25 | 1.50 |
| 2026-06-01 | 1.50 |
| 2026-06-08 | 1.60 |
| 2026-06-15 | 1.70 |
| 2026-06-22 | 1.70 |
| 2026-06-29 | 1.70 |
| 2026-07-06 | 1.80 |
| 2026-07-13 | 1.90 |
Current event vs. historical analogs (aligned by season offset from onset)
Onset = first season of an unbroken run of same-phase (El Nino/La Nina) classified seasons, walking backward from a known in-episode index. Offset 0 = onset season; each subsequent offset is the next overlapping 3-month season. 'Percent of strongest' compares the current event's anomaly at each offset only to analog seasons that have reached that same offset, using whichever analog is strongest at that specific stage (not each analog's all-time peak).
View as a table
| Offset | Current | 1982-83 | 1997-98 | 2015-16 | 2023-24 |
|---|---|---|---|---|---|
| 0 | 0.70 | 0.50 | 0.60 | 1.10 | 0.50 |
| 1 | 0.94 | 0.70 | 1.00 | 1.50 | 0.80 |
| 2 | 1.20 | 1.00 | 1.50 | 0.60 | 1.10 |
CPC seasonal outlook: chance of El Nino / Neutral / La Nina
View as a table
| Season | El Nino | Neutral | La Nina |
|---|---|---|---|
| JJA 2026 | 100% | 0% | 0% |
| JAS 2026 | 100% | 0% | 0% |
| ASO 2026 | 100% | 0% | 0% |
| SON 2026 | 100% | 0% | 0% |
| OND 2026 | 99% | 1% | 0% |
| NDJ 2026 | 99% | 1% | 0% |
| DJF 2027 | 99% | 1% | 0% |
| JFM 2027 | 97% | 3% | 0% |
| FMA 2027 | 90% | 9% | 1% |
Strength probability, OND 2026
Shown as a full distribution, never a single headline number -- see why.
View as a table
| Weak | Moderate | Strong | Very strong |
|---|---|---|---|
| 2% | 6% | 11% | 81% |
Next scheduled updates
CPC ENSO Diagnostic Discussion: (static date -- second Thursday, monthly)
NOAA seasonal winter outlook: (estimated; the biggest traffic day of the arc)
What changed this month
El Nino is expected to strengthen through the remainder of 2026, with a 97% chance of persisting through early spring 2027.
El Nino is quieting this year's Atlantic hurricane season -- the same wind-shear pattern behind the wet Gulf/Southeast winter tendency also suppresses tropical development. Track it live at HurriTrack, or read our El Nino & hurricane season explainer.
SST anomaly map
For the live sea-surface-temperature anomaly map, see NOAA's PSL El Nino Index Dashboard (official NOAA product, opens in a new tab).