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PROGNOSTIC DISCUSSION FOR LONG-LEAD HAWAIIAN OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
830AM EDT THU SEP 18 2025
MONTHLY FORECAST DISCUSSION VALID OCTOBER 2025
SEA-SURFACE TEMPERATURE (SST) ANOMALIES IN THE RANGE OF 0 TO +1 DEGREES CELSIUS
(C) WERE OBSERVED AROUND THE HAWAIIAN ISLANDS (KAUAI, OAHU, MAUI AND THE BIG
ISLAND) DURING THE PREVIOUS WEEK.
FROM JANUARY THROUGH AUGUST 2025, RAINFALL TOTAL ACCUMULATIONS WERE:
LIHUE AIRPORT 12.10 INCHES (55 PERCENT OF AVERAGE)
HONOLULU AIRPORT 8.97 INCHES (94 PERCENT OF AVERAGE)
KAHULUI AIRPORT 6.62 INCHES (64 PERCENT OF AVERAGE)
HILO AIRPORT 35.41 INCHES (47 PERCENT OF AVERAGE)
MOST CLIMATE MODELS OF THE NORTH AMERICAN MULTI-MODEL ENSEMBLE (NMME) AND THE
INTERNATIONAL MULTI-MODEL ENSEMBLE (IMME/C3S) PREDICT POSITIVE SST ANOMALIES
AROUND MOST OF THE HAWAIIAN ISLANDS IN OCTOBER 2025. MOST MODELS PREDICT WEAK
OR NEAR ZERO SST ANOMALIES NEAR THE SOUTHEASTERN HAWAIIAN ISLANDS IN OCTOBER
2025. BASED ON MODEL SST AND SURFACE AIR TEMPERATURE FORECASTS, ABOVE NORMAL
TEMPERATURES ARE FAVORED FOR KAUAI (LIHUE), OAHU (HONOLULU) AND MAUI (KAHULUI)
WITH GREATER PROBABILITIES FOR THE NORTHWESTERN ISLANDS OF OAHU AND KAUAI.
EQUAL CHANCES (EC) FOR ABOVE, NEAR OR BELOW NORMAL TEMPERATURES ARE INDICATED
FOR THE BIG ISLAND OF HAWAII (HILO) IN OCTOBER 2025, WHERE TOOLS ARE LESS
CONSISTENT.
FOR THE SEPTEMBER 2025 PRECIPITATION OUTLOOK, THE PROBABILITY OF BELOW NORMAL
PRECIPITATION IS ELEVATED FOR OAHU, MAUI AND THE BIG ISLAND, WHILE EQUAL
CHANCES (EC) FOR ABOVE, NEAR OR BELOW NORMAL TEMPERATURES ARE INDICATED FOR
KAUAI, CONSISTENT WITH MOST MODELS OF THE NMME AND IMME.
TEMPERATURE PRECIPITATION
FCST AVE LIM FCST BLW MEDIAN ABV
HILO EC 75.7 0.5 B55 7.8 8.6 12.1
KAHULUI A45 78.2 0.4 B50 0.3 0.6 1.1
HONOLULU A55 80.2 0.5 B45 0.5 1.3 1.9
LIHUE A60 78.1 0.3 EC 2.5 3.3 4.2
SEASONAL FORECAST DISCUSSION VALID OND 2025 - OND 2026
REFER TO THE PROGNOSTIC DISCUSSION OF THE LONG-LEAD SEASONAL OUTLOOKS FOR THE
CONTIGUOUS U.S. (CONUS) AND ALASKA FOR FURTHER DESCRIPTION OF THE EL NIñO
SOUTHERN OSCILLATION (ENSO) OUTLOOK AND OTHER CLIMATE CONDITIONS RELEVANT TO
THE SEASONAL OUTLOOK.
ENSO-NEUTRAL CONDITIONS CONTINUED INTO SEPTEMBER. EQUATORIAL SEA SURFACE
TEMPERATURES (SSTS) WERE ABOVE AVERAGE IN THE WESTERN PACIFIC OCEAN, AND WERE
NEAR-TO-BELOW AVERAGE ACROSS MOST OF THE CENTRAL AND EASTERN PACIFIC.
BELOW-AVERAGE SUBSURFACE OCEAN TEMPERATURES STRENGTHENED ACROSS THE CENTRAL AND
EASTERN PACIFIC, WHILE ABOVE-AVERAGE SUBSURFACE TEMPERATURES PERSISTED IN THE
WESTERN PACIFIC. ABOVE-AVERAGE OUTGOING LONGWAVE RADIATION (OLR), ASSOCIATED
WITH SUPPRESSED CONVECTION AND PRECIPITATION, ARE OBSERVED OVER THE DATE LINE.
LOW-LEVEL WIND ANOMALIES WERE EASTERLY OVER MOST OF THE EQUATORIAL PACIFIC
OCEAN, WHILE UPPER-LEVEL WIND ANOMALIES WERE WESTERLY OVER THE EAST-CENTRAL
EQUATORIAL PACIFIC. THE CPC ENSO OUTLOOK FORECASTS A TRANSITION FROM
ENSO-NEUTRAL TO LA NINA IN THE NEXT COUPLE OF MONTHS, WITH A 71% CHANCE OF LA
NIñA DURING OCTOBER-NOVEMBER-DECEMBER (OND) 2025. LA NIñA IS FAVORED BUT
CHANCES DECREASE TO 54% IN DECEMBER-JANUARY- FEBRUARY (DJF) 2026.
ENHANCED PROBABILITIES FOR ABOVE NORMAL TEMPERATURES ARE PREDICTED IN THE
OUTLOOK FOR KAUAI, OAHU, MAUI, AND THE BIG ISLAND FROM OND 2025, THROUGH
FEBRUARY-MARCH-APRIL (FMA) 2026, SUPPORTED BY NEARLY ALL DYNAMICAL MODEL
FORECASTS FROM THE NMME AND C3S. PROBABILITIES FOR ABOVE NORMAL TEMPERATURES
ARE GREATER FOR NORTHWESTERN ISLANDS OF HAWAII IN EARLY SEASONS, FOLLOWING
CALIBRATED MODEL GUIDANCE FROM THE NMME. DUE TO INCREASING UNCERTAINTY IN THE
STATE OF ENSO AND WEAKENING SIGNALS IN FORECAST GUIDANCE AT LONGER LEADS, EQUAL
CHANCES (EC) FOR ABOVE, NEAR OR BELOW NORMAL TEMPERATURES ARE INDICATED FOR
HAWAII BEGINNING IN MARCH-APRIL-MAY (MAM) 2026 AND EXTENDING THROUGH LONGER
LEADS.
ENHANCED PROBABILITIES FOR BELOW NORMAL PRECIPITATION ARE FORECAST OVER THE BIG
ISLAND FOR OND 2025, SUPPORTED BY MOST OF DYNAMICAL MODEL FORECAST TOOLS. EQUAL
CHANCES (EC) FOR ABOVE, NEAR OR BELOW NORMAL PRECIPITATION ARE INDICATED FOR
THE ISLANDS OF KAUAI, OAHU, AND MAUI IN OND 2026 AND FOR THE BIG ISLAND IN NDJ
2025. ENHANCED PROBABILITIES FOR ABOVE NORMAL PRECIPITATION ARE FORECAST FOR
THE ISLANDS OF KAUAI, OAHU, AND MAUI BEGINNING IN NOVEMBER-DECEMBER-JANUARY
(NDJ) 2025 AND FOR THE BIG ISLAND BEGINNING IN DJF 2026, CONTINUING THROUGH FMA
2026, CONSISTENT WITH MOST DYNAMICAL MODEL FORECASTS, AS WELL DECADAL TIMESCALE
PRECIPITATION TRENDS. BEGINNING IN MAM 2026 AND EXTENDING THROUGH LONGER LEADS,
EC IS INDICATED IN THE SEASONAL PRECIPITATION OUTLOOK, DUE TO UNCERTAINTY IN
THE STATE OF ENSO AND WEAKER SIGNALS IN FORECAST TOOLS.
HILO
TEMPERATURE PRECIPITATION
FCST AVE LIM FCST BLW MEDIAN ABV
OND 2025 A40 75.5 0.4 B40 28.3 34.5 42.0
NDJ 2025 A40 74.2 0.4 EC 26.4 36.6 43.0
DJF 2026 A40 72.8 0.4 A40 19.6 30.2 33.3
JFM 2026 A40 71.8 0.4 A45 22.0 32.0 44.5
FMA 2026 A40 71.7 0.4 A45 24.6 34.1 45.5
MAM 2026 EC 72.0 0.5 EC 22.5 28.4 34.0
AMJ 2026 EC 72.9 0.5 EC 21.4 23.7 29.0
MJJ 2026 EC 74.0 0.4 EC 20.2 27.5 29.1
JJA 2026 EC 75.2 0.4 EC 19.4 27.2 31.4
JAS 2026 EC 76.1 0.4 EC 25.2 28.6 33.4
ASO 2026 EC 76.4 0.4 EC 26.1 28.8 33.3
SON 2026 EC 76.2 0.4 EC 24.3 30.2 40.8
OND 2026 EC 75.5 0.4 EC 28.3 34.5 42.0
KAHULUI
TEMPERATURE PRECIPITATION
FCST AVE LIM FCST BLW MEDIAN ABV
OND 2025 A50 77.8 0.4 EC 4.2 5.3 8.1
NDJ 2025 A45 75.9 0.4 A40 5.2 7.6 9.5
DJF 2026 A45 73.8 0.4 A45 4.6 6.9 8.7
JFM 2026 A40 72.5 0.4 A45 4.2 6.2 8.2
FMA 2026 A40 72.3 0.4 A45 3.2 4.1 6.4
MAM 2026 EC 73.0 0.4 EC 2.5 3.5 4.6
AMJ 2026 EC 74.3 0.5 EC 1.2 1.6 2.2
MJJ 2026 EC 76.0 0.5 EC 0.7 1.1 1.8
JJA 2026 EC 77.7 0.4 EC 0.7 1.1 1.5
JAS 2026 EC 79.0 0.4 EC 0.8 1.1 1.6
ASO 2026 EC 79.4 0.4 EC 0.8 1.6 2.5
SON 2026 EC 79.1 0.4 EC 2.1 3.3 4.8
OND 2026 EC 77.8 0.4 EC 4.2 5.3 8.1
HONOLULU
TEMPERATURE PRECIPITATION
FCST AVE LIM FCST BLW MEDIAN ABV
OND 2025 A60 80.0 0.4 EC 4.4 6.4 8.5
NDJ 2025 A55 77.7 0.5 A40 3.9 5.6 8.8
DJF 2026 A45 75.3 0.5 A45 3.7 5.6 8.6
JFM 2026 A40 73.9 0.4 A50 2.1 4.6 7.8
FMA 2026 A40 73.8 0.4 A50 1.9 3.2 4.7
MAM 2026 EC 74.8 0.4 EC 1.8 2.6 3.0
AMJ 2026 EC 76.3 0.4 EC 1.2 1.6 1.8
MJJ 2026 EC 78.2 0.4 EC 0.8 1.4 1.6
JJA 2026 EC 79.9 0.4 EC 0.7 0.8 1.3
JAS 2026 EC 81.3 0.4 EC 1.0 1.4 1.7
ASO 2026 EC 81.7 0.4 EC 1.6 2.4 3.1
SON 2026 EC 81.4 0.4 EC 2.5 4.0 5.6
OND 2026 EC 80.0 0.4 EC 4.4 6.4 8.5
LIHUE
TEMPERATURE PRECIPITATION
FCST AVE LIM FCST BLW MEDIAN ABV
OND 2025 A65 77.8 0.3 EC 9.2 11.7 15.6
NDJ 2025 A55 75.7 0.3 A40 8.6 12.1 16.9
DJF 2026 A45 73.6 0.4 A45 7.5 8.4 14.0
JFM 2026 A40 72.2 0.4 A50 6.5 8.8 13.8
FMA 2026 A40 72.1 0.5 A50 5.8 8.4 9.9
MAM 2026 EC 72.8 0.5 EC 5.3 6.6 8.0
AMJ 2026 EC 74.2 0.5 EC 4.7 5.5 6.0
MJJ 2026 EC 76.0 0.5 EC 4.9 5.4 5.9
JJA 2026 EC 77.7 0.4 EC 4.4 5.3 6.9
JAS 2026 EC 79.0 0.3 EC 5.3 6.1 7.8
ASO 2026 EC 79.4 0.3 EC 6.2 7.9 8.4
SON 2026 EC 79.1 0.3 EC 9.2 10.0 11.2
OND 2026 EC 77.8 0.3 EC 9.2 11.7 15.6
FORECASTER: LUKE HE
ANOMALIES ARE BASED ON THE 1991-2020 MEANS.
CLARIFICATION: EC INDICATED EQUAL CHANCES THAT THE PREDICTED PARAMETER WILL
FALL INTO ANY ONE OF THE THREE CATEGORIES, WHOSE BOUNDARIES ARE SPECIFIC IN THE
TABLES ABOVE. A FORECAST SPECIFICATION OF EC MEANS THERE IS NO PARTICULATE TILT
OF THE ODDS TOWARD ABOVE NORMAL OR BELOW NORMAL CONDITIONS IN THE OUTLOOK. FOR
EXAMPLE A40 MEANS A 40% CHANCE THAT THE AVERAGE TEMPERATURE OR TOTAL
PRECIPITATION WILL BE IN THE ABOVE NORMAL CLASS, B40 MEANS A 40% CHANCE THAT
THE AVERAGE TEMPERATURE OR TOTAL PRECIPITATION WILL BE IN THE BELOW NORMAL
CLASS, AND N35 MEANS A 35% PROBABILITY THAT THE AVERAGE TEMPERATURE OR TOTAL
PRECIPITATION WILL BE IN THE NEAR NORMAL CLASS. WHEN EC IS SPECIFIED, ALL
CATEGORIES ARE EQUALLY LIKELY.
NOTE - THESE OUTLOOKS ARE INTENDED FOR USE PRIOR TO THE START OF THE VALID
PERIODS. WITHIN ANY VALID PERIOD, OBSERVATIONS AND SHORTER RANGE FORECASTS
SHOULD BE CONSULTED. ALSO, THIS SET OF OUTLOOKS WILL BE SUPERSEDED BY THE
ISSUANCES OF THE NEW SET NET MONTH, ON THU OCT 16, 2025.
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