Seasonal Rainfall Outlook Platform
Historical skill · Feb 2026 · FMAM 2026 — February initialization · FMAM rainfall contribution domain

Historical skill · Feb 2026

How forecasts made with the same method scored in past years against climatology (the observed frequency of each tercile in the training years, about one-third each). The main number is the cross-validated 1993–2016 score: each year is forecast with parameters fitted without that year. Later years are exploratory: they were seen while the method was chosen.

Takeaway — Feb 2026

Cross-validated 1993–2016 skill is +0.137 (interval +0.050 to +0.234, above zero): a moderate improvement over climatology. The exploratory 2017–2025 result (+0.049) is encouraging but those years were inspected during method selection. The 2026 verification (+0.009) is one season and does not override the historical uncertainty.

FMAM 2026 (February initialization), FMAM rainfall contribution domain: probability skill (RPSS) of the final method against climatology, with whole-year 95% intervals
TargetCross-validated 1993–2016 (main)In wordsExploratory 2017–2025
Feb+0.137 (+0.050 to +0.234)Moderate improvement over climatology (interval above zero)+0.049 (−0.017 to +0.128)
FMAM+0.017 (−0.038 to +0.067)Small estimated improvement; skill uncertain+0.061 (+0.029 to +0.095)
Mar+0.011 (−0.020 to +0.042)Small estimated improvement; skill uncertain+0.041 (+0.007 to +0.080)
Apr+0.011 (−0.032 to +0.048)Small estimated improvement; skill uncertain+0.015 (−0.009 to +0.042)
May+0.007 (−0.051 to +0.050)Small estimated improvement; skill uncertain+0.017 (−0.033 to +0.057)

RPSS +0.05 means a 5% lower ranked probability score than climatology. An interval that includes zero means the gain is not established.

Technical detail: years better, p-values and blend weights
TargetYears better (cross-validated)p (one target / Holm)Years better (exploratory)Blend weight λ
FMAM15 of 240.276 / 1.0008 of 90.40
Feb16 of 240.002 / 0.0125 of 90.50
Mar15 of 240.251 / 1.0007 of 90.73
Apr16 of 240.305 / 1.0005 of 90.58
May17 of 240.434 / 1.0008 of 90.55

Each interval and one-target p-value describes that target alone. Because 5 targets are examined, the Holm-adjusted p is the stricter test: Feb remains significant after adjustment. λ is the weight given to climatology in the blend (higher = closer to climatology).

Historical verification explorer

The evidence behind the scores above, for Feb 2026 in this area. Choose the evaluation period; all diagnostics use the blended probabilities against climatology.

Evaluation
Cross-validated (nested leave-one-year-out), 1993–2016
Benchmark
Climatology: observed tercile frequencies of the training years (about one-third each)
Area
FMAM rainfall contribution domain; probabilities on 91% of it on average
Sample
24 years, 24,431 cell-years. Cells within a year are spatially correlated, so the independent sample is closer to one value per year.

Performance by year

Probability skill (RPSS) of each year; better than climatology in 16 of 24 years. Weakest years: 2004 (−0.179), 2003 (−0.137), 2013 (−0.046).

Better than climatologyWorse
−0.500.00+0.50+1.001993: RPSS +0.626 (forecast RPS 0.200, climatology 0.537; 1021 cells)199319931994: RPSS +0.122 (forecast RPS 0.433, climatology 0.493; 1022 cells)1995: RPSS +0.354 (forecast RPS 0.322, climatology 0.499; 1022 cells)1996: RPSS −0.023 (forecast RPS 0.434, climatology 0.424; 1022 cells)1997: RPSS +0.183 (forecast RPS 0.414, climatology 0.506; 1022 cells)19971998: RPSS +0.398 (forecast RPS 0.304, climatology 0.505; 1022 cells)1999: RPSS +0.064 (forecast RPS 0.421, climatology 0.450; 1021 cells)2000: RPSS +0.059 (forecast RPS 0.497, climatology 0.528; 1018 cells)2001: RPSS +0.065 (forecast RPS 0.354, climatology 0.378; 1022 cells)20012002: RPSS +0.074 (forecast RPS 0.421, climatology 0.455; 1021 cells)2003: RPSS −0.137 (forecast RPS 0.532, climatology 0.468; 1021 cells)2004: RPSS −0.179 (forecast RPS 0.436, climatology 0.370; 1021 cells)20042005: RPSS −0.021 (forecast RPS 0.394, climatology 0.386; 1022 cells)20052006: RPSS −0.025 (forecast RPS 0.489, climatology 0.477; 1013 cells)2007: RPSS +0.422 (forecast RPS 0.264, climatology 0.456; 1021 cells)2008: RPSS +0.100 (forecast RPS 0.411, climatology 0.456; 1021 cells)2009: RPSS +0.083 (forecast RPS 0.360, climatology 0.392; 1019 cells)20092010: RPSS +0.563 (forecast RPS 0.235, climatology 0.537; 961 cells)2011: RPSS −0.001 (forecast RPS 0.368, climatology 0.367; 1021 cells)2012: RPSS +0.183 (forecast RPS 0.375, climatology 0.458; 1022 cells)2013: RPSS −0.046 (forecast RPS 0.455, climatology 0.434; 1021 cells)20132014: RPSS +0.037 (forecast RPS 0.404, climatology 0.420; 1020 cells)2015: RPSS +0.073 (forecast RPS 0.384, climatology 0.414; 1022 cells)2016: RPSS −0.042 (forecast RPS 0.477, climatology 0.458; 1013 cells)

Reliability

below normalnear normalabove normal
0.00.00.20.20.40.40.60.60.80.81.01.0below normal: forecast 18%, observed 26% (11736 cell-years)below normal: forecast 25%, observed 22% (2651 cell-years)below normal: forecast 36%, observed 32% (2602 cell-years)below normal: forecast 45%, observed 45% (3171 cell-years)below normal: forecast 55%, observed 58% (3080 cell-years)below normal: forecast 63%, observed 69% (1191 cell-years)near normal: forecast 17%, observed 20% (6470 cell-years)near normal: forecast 25%, observed 25% (6010 cell-years)near normal: forecast 35%, observed 36% (4056 cell-years)near normal: forecast 45%, observed 43% (2849 cell-years)near normal: forecast 55%, observed 44% (3213 cell-years)near normal: forecast 62%, observed 33% (1833 cell-years)above normal: forecast 19%, observed 6% (4042 cell-years)above normal: forecast 25%, observed 20% (9136 cell-years)above normal: forecast 34%, observed 37% (4014 cell-years)above normal: forecast 45%, observed 52% (1687 cell-years)above normal: forecast 56%, observed 76% (1660 cell-years)above normal: forecast 65%, observed 69% (3892 cell-years)Forecast probability

Points on the dashed diagonal are reliable: events forecast with probability p happen p of the time. Points flatter than the diagonal mean over-confident probabilities. Open points have fewer than 122 cell-years (0.5% of the sample, at least 50) and are not joined. Hover a point for its count.

Reliability table (forecast bins, observed frequency, counts)
CategoryBinMean forecastObserved frequencyCell-years
below normal10%–20%18%26%11,736
below normal20%–30%25%22%2,651
below normal30%–40%36%32%2,602
below normal40%–50%45%45%3,171
below normal50%–60%55%58%3,080
below normal60%–70%63%69%1,191
near normal10%–20%17%20%6,470
near normal20%–30%25%25%6,010
near normal30%–40%35%36%4,056
near normal40%–50%45%43%2,849
near normal50%–60%55%44%3,213
near normal60%–70%62%33%1,833
above normal10%–20%19%6%4,042
above normal20%–30%25%20%9,136
above normal30%–40%34%37%4,014
above normal40%–50%45%52%1,687
above normal50%–60%56%76%1,660
above normal60%–70%65%69%3,892

How strong are the signals?

Share of cell-years by the leading tercile probability.

weak (<40%)
9%
moderate (40–50%)
31%
strong (50–60%)
33%
very strong (≥60%)
28%
Category Brier scores (lower is better) and Brier skill against climatology
CategoryForecastClimatologyBrier skill
below normal0.21200.2271+0.067
near normal0.21330.2127−0.003
above normal0.17900.2258+0.207

Rainfall amounts

Historical rainfall-amount diagnostics (CRPS, CRPSS and amount errors) have not been generated for Feb 2026 in this area and period; this needs a separate cross-validated amount evaluation. Single-season amount scores are in the Verification section.

Historical performance by rainfall region

Probability skill by rainfall region (full regional matrix)
FMAM 2026: probability skill (RPSS) by rainfall region, cross-validated 1993–2016, with whole-year 95% intervals and years better than climatology
RegionFMAMFebMarAprMay
All Ethiopia+0.021 (−0.031 to +0.069) 15/24 yrs+0.126 (+0.043 to +0.217) 18/24 yrs+0.011 (−0.017 to +0.038) 15/24 yrs+0.009 (−0.034 to +0.044) 15/24 yrs+0.008 (−0.042 to +0.047) 16/24 yrs
R0 arid / marginal+0.023 (−0.072 to +0.103) 15/24 yrs+0.057 (−0.081 to +0.206) 13/24 yrs−0.005 (−0.058 to +0.044) 15/24 yrs−0.028 (−0.102 to +0.038) 13/24 yrs−0.015 (−0.079 to +0.040) 13/24 yrs
R1 western unimodal+0.019 (−0.035 to +0.067) 18/24 yrs+0.156 (+0.068 to +0.248) 18/24 yrs+0.009 (−0.018 to +0.034) 15/24 yrs+0.016 (−0.024 to +0.047) 17/24 yrs+0.009 (−0.033 to +0.046) 15/24 yrs
R2 Belg–Kiremt+0.037 (−0.050 to +0.108) 17/24 yrs+0.166 (+0.076 to +0.264) 20/24 yrs+0.023 (−0.017 to +0.058) 16/24 yrs−0.001 (−0.063 to +0.052) 14/24 yrs+0.009 (−0.051 to +0.059) 16/24 yrs
R3 Gu–Deyr+0.012 (−0.042 to +0.064) 15/24 yrs+0.082 (−0.006 to +0.180) 14/24 yrs+0.006 (−0.030 to +0.041) 14/24 yrs+0.017 (−0.034 to +0.064) 16/24 yrs+0.009 (−0.066 to +0.062) 19/24 yrs
FMAM rainfall contribution domain+0.017 (−0.038 to +0.067) 15/24 yrs+0.137 (+0.050 to +0.234) 16/24 yrs+0.011 (−0.020 to +0.042) 15/24 yrs+0.011 (−0.032 to +0.048) 16/24 yrs+0.007 (−0.051 to +0.050) 17/24 yrs
FMAM main-season rainfall domain (Belg / Gu / Ganna, >=40% of annual)+0.013 (−0.040 to +0.066) 16/24 yrs+0.080 (−0.005 to +0.176) 14/24 yrs+0.007 (−0.029 to +0.042) 15/24 yrs+0.013 (−0.041 to +0.060) 17/24 yrs+0.009 (−0.066 to +0.062) 18/24 yrs

Positive values mean lower RPS than climatology. Intervals resample whole years; regions are the fixed 1993–2025 rainfall regimes, and the last rows are this cycle's rainfall domains. Regional results are noisier than national ones.