Where does a season's rain matter? Before a forecast domain is chosen, this review computes the observed climatology (seasonal
total, annual total and the season's share), compares it with EMI's published long-term maps, and tests every combination of rainfall
and annual-share cutoffs. Cutoffs are chosen for what the domain means climatologically, never to improve a forecast score.
Evidence only: no candidate has been selected for ONDJ, so the forecast products keep their current domain (ONDJ R3 (Deyr) rainfall domain).
ONDJ climatology from CHIRPS v3.0 1993–2024 · built 2026-10-10 · Full review report
No candidate has been selected yet. The review shows the evidence; a domain is exported to the forecast products only after an explicit selection.
Climatology References Candidate domains Assessment
No EMI long-term maps are registered for ONDJ. Evidence for the ONDJ rainfall domain. No candidate is selected: the operational ONDJ domain (R3 Deyr) is unchanged. No EMI long-term Bega maps are registered: the Bega 2026/27 Seasonal Climate Forecast had no document when checked (2026-10-10). ONDJ months are summed within each calendar year (January of the same year); the climatological mean is unaffected by the pairing.
Registered climatology references Reference Comparison mode Why not higher Digitization Outline match (IoU) Control / check error
ONDJ rainfall ≥ 30 mm ≥ 60 mm ≥ 120 mm ≥ 200 mm
Share of annual ≥ 10% ≥ 20% ≥ 30% ≥ 40%
Comparison — threshold candidates — Current ONDJ R3 (Deyr) rainfall domain: R3 membership, ONDJ >= 30 mm, patches < 3 cells removed Earlier ONDJ rainfall domain (not in use): ONDJ >= 120 mm and >= 20% of annual (1993-2024) 40% contribution rule: ONDJ >= 40% of annual and >= 60 mm (no cleanup) Wettest-season rule: ONDJ wetter than FMAM and JJAS, >= 60 mm (no cleanup) Candidate mm30_share10 (blue: included; dark grey: insufficient data) mm30_share10 Measure Value Included area 862,899 km² (76.4% of Ethiopia) Agreement with EMI-implied membership No reference registered Domain files NetCDF · GeoJSON outline Unknown area 4 km² Baseline 1981-2010 unavailable: 12 of 30 years are not in the data (1981-1992); the period is not shortened. Baseline 1991-2020 unavailable: 2 of 30 years are not in the data (1991-1992); the period is not shortened. Baseline 1996-2025 +11,341 km² / −1,777 km²
Share of each EMI rainfall region included Region Included I Northeast 50.5% II Northwest 23.2% III Southwest 94% IV Central 32.1% V East 93.6% VI South Highland 100% VII South 100% VIII South-Southeast lowlands 100%
Candidate mm30_share20 (blue: included; dark grey: insufficient data) mm30_share20 Measure Value Included area 482,905 km² (42.7% of Ethiopia) Agreement with EMI-implied membership No reference registered Domain files NetCDF · GeoJSON outline Unknown area 4 km² Baseline 1981-2010 unavailable: 12 of 30 years are not in the data (1981-1992); the period is not shortened. Baseline 1991-2020 unavailable: 2 of 30 years are not in the data (1991-1992); the period is not shortened. Baseline 1996-2025 +1,177 km² / −0 km²
Share of each EMI rainfall region included Region Included I Northeast 3.9% II Northwest 0% III Southwest 14.3% IV Central 0% V East 11.5% VI South Highland 75.6% VII South 98.3% VIII South-Southeast lowlands 96.3%
Candidate mm30_share30 (blue: included; dark grey: insufficient data) mm30_share30 Measure Value Included area 309,466 km² (27.4% of Ethiopia) Agreement with EMI-implied membership No reference registered Domain files NetCDF · GeoJSON outline Unknown area 4 km² Baseline 1981-2010 unavailable: 12 of 30 years are not in the data (1981-1992); the period is not shortened. Baseline 1991-2020 unavailable: 2 of 30 years are not in the data (1991-1992); the period is not shortened. Baseline 1996-2025 +6,125 km² / −1,448 km²
Share of each EMI rainfall region included Region Included I Northeast 0% II Northwest 0% III Southwest 0% IV Central 0% V East 0% VI South Highland 24.5% VII South 12.3% VIII South-Southeast lowlands 84%
Candidate mm30_share40 (blue: included; dark grey: insufficient data) mm30_share40 Measure Value Included area 145,332 km² (12.9% of Ethiopia) Agreement with EMI-implied membership No reference registered Domain files NetCDF · GeoJSON outline Unknown area 4 km² Baseline 1981-2010 unavailable: 12 of 30 years are not in the data (1981-1992); the period is not shortened. Baseline 1991-2020 unavailable: 2 of 30 years are not in the data (1991-1992); the period is not shortened. Baseline 1996-2025 +4,301 km² / −3,158 km²
Share of each EMI rainfall region included Region Included I Northeast 0% II Northwest 0% III Southwest 0% IV Central 0% V East 0% VI South Highland 0% VII South 0% VIII South-Southeast lowlands 44%
Candidate mm60_share10 (blue: included; dark grey: insufficient data) mm60_share10 Measure Value Included area 810,503 km² (71.7% of Ethiopia) Agreement with EMI-implied membership No reference registered Domain files NetCDF · GeoJSON outline Unknown area 4 km² Baseline 1981-2010 unavailable: 12 of 30 years are not in the data (1981-1992); the period is not shortened. Baseline 1991-2020 unavailable: 2 of 30 years are not in the data (1991-1992); the period is not shortened. Baseline 1996-2025 +6,816 km² / −935 km²
Share of each EMI rainfall region included Region Included I Northeast 29% II Northwest 23.2% III Southwest 94% IV Central 32.1% V East 79.1% VI South Highland 100% VII South 100% VIII South-Southeast lowlands 99.2%
Candidate mm60_share20 (blue: included; dark grey: insufficient data) mm60_share20 Measure Value Included area 480,894 km² (42.6% of Ethiopia) Agreement with EMI-implied membership No reference registered Domain files NetCDF · GeoJSON outline Unknown area 4 km² Baseline 1981-2010 unavailable: 12 of 30 years are not in the data (1981-1992); the period is not shortened. Baseline 1991-2020 unavailable: 2 of 30 years are not in the data (1991-1992); the period is not shortened. Baseline 1996-2025 +1,177 km² / −0 km²
Share of each EMI rainfall region included Region Included I Northeast 3% II Northwest 0% III Southwest 14.3% IV Central 0% V East 10.9% VI South Highland 75.6% VII South 98.3% VIII South-Southeast lowlands 96.3%
Candidate mm60_share30 (blue: included; dark grey: insufficient data) mm60_share30 Measure Value Included area 309,466 km² (27.4% of Ethiopia) Agreement with EMI-implied membership No reference registered Domain files NetCDF · GeoJSON outline Unknown area 4 km² Baseline 1981-2010 unavailable: 12 of 30 years are not in the data (1981-1992); the period is not shortened. Baseline 1991-2020 unavailable: 2 of 30 years are not in the data (1991-1992); the period is not shortened. Baseline 1996-2025 +6,125 km² / −1,448 km²
Share of each EMI rainfall region included Region Included I Northeast 0% II Northwest 0% III Southwest 0% IV Central 0% V East 0% VI South Highland 24.5% VII South 12.3% VIII South-Southeast lowlands 84%
Candidate mm60_share40 (blue: included; dark grey: insufficient data) mm60_share40 Measure Value Included area 145,332 km² (12.9% of Ethiopia) Agreement with EMI-implied membership No reference registered Domain files NetCDF · GeoJSON outline Unknown area 4 km² Baseline 1981-2010 unavailable: 12 of 30 years are not in the data (1981-1992); the period is not shortened. Baseline 1991-2020 unavailable: 2 of 30 years are not in the data (1991-1992); the period is not shortened. Baseline 1996-2025 +4,301 km² / −3,158 km²
Share of each EMI rainfall region included Region Included I Northeast 0% II Northwest 0% III Southwest 0% IV Central 0% V East 0% VI South Highland 0% VII South 0% VIII South-Southeast lowlands 44%
Candidate mm120_share10 (blue: included; dark grey: insufficient data) mm120_share10 Measure Value Included area 643,070 km² (56.9% of Ethiopia) Agreement with EMI-implied membership No reference registered Domain files NetCDF · GeoJSON outline Unknown area 4 km² Baseline 1981-2010 unavailable: 12 of 30 years are not in the data (1981-1992); the period is not shortened. Baseline 1991-2020 unavailable: 2 of 30 years are not in the data (1991-1992); the period is not shortened. Baseline 1996-2025 +9,856 km² / −3,963 km²
Share of each EMI rainfall region included Region Included I Northeast 9.9% II Northwest 21.6% III Southwest 90.6% IV Central 24.9% V East 35.8% VI South Highland 97.9% VII South 100% VIII South-Southeast lowlands 75.9%
Candidate mm120_share20 (blue: included; dark grey: insufficient data) mm120_share20 Measure Value Included area 407,612 km² (36.1% of Ethiopia) Agreement with EMI-implied membership No reference registered Domain files NetCDF · GeoJSON outline Unknown area 4 km² Baseline 1981-2010 unavailable: 12 of 30 years are not in the data (1981-1992); the period is not shortened. Baseline 1991-2020 unavailable: 2 of 30 years are not in the data (1991-1992); the period is not shortened. Baseline 1996-2025 +4,574 km² / −3,209 km²
Share of each EMI rainfall region included Region Included I Northeast 0.4% II Northwest 0% III Southwest 14.3% IV Central 0% V East 10.1% VI South Highland 74.9% VII South 98.3% VIII South-Southeast lowlands 75.9%
Candidate mm120_share30 (blue: included; dark grey: insufficient data) mm120_share30 Measure Value Included area 277,158 km² (24.5% of Ethiopia) Agreement with EMI-implied membership No reference registered Domain files NetCDF · GeoJSON outline Unknown area 4 km² Baseline 1981-2010 unavailable: 12 of 30 years are not in the data (1981-1992); the period is not shortened. Baseline 1991-2020 unavailable: 2 of 30 years are not in the data (1991-1992); the period is not shortened. Baseline 1996-2025 +9,937 km² / −3,211 km²
Share of each EMI rainfall region included Region Included I Northeast 0% II Northwest 0% III Southwest 0% IV Central 0% V East 0% VI South Highland 24.5% VII South 12.3% VIII South-Southeast lowlands 74.2%
Candidate mm120_share40 (blue: included; dark grey: insufficient data) mm120_share40 Measure Value Included area 125,165 km² (11.1% of Ethiopia) Agreement with EMI-implied membership No reference registered Domain files NetCDF · GeoJSON outline Unknown area 4 km² Baseline 1981-2010 unavailable: 12 of 30 years are not in the data (1981-1992); the period is not shortened. Baseline 1991-2020 unavailable: 2 of 30 years are not in the data (1991-1992); the period is not shortened. Baseline 1996-2025 +6,343 km² / −2,903 km²
Share of each EMI rainfall region included Region Included I Northeast 0% II Northwest 0% III Southwest 0% IV Central 0% V East 0% VI South Highland 0% VII South 0% VIII South-Southeast lowlands 37.9%
Candidate mm200_share10 (blue: included; dark grey: insufficient data) mm200_share10 Measure Value Included area 299,402 km² (26.5% of Ethiopia) Agreement with EMI-implied membership No reference registered Domain files NetCDF · GeoJSON outline Unknown area 4 km² Baseline 1981-2010 unavailable: 12 of 30 years are not in the data (1981-1992); the period is not shortened. Baseline 1991-2020 unavailable: 2 of 30 years are not in the data (1991-1992); the period is not shortened. Baseline 1996-2025 +3,302 km² / −2,291 km²
Share of each EMI rainfall region included Region Included I Northeast 0% II Northwest 6.6% III Southwest 70.5% IV Central 0.8% V East 5.5% VI South Highland 81.1% VII South 96.9% VIII South-Southeast lowlands 14.1%
Candidate mm200_share20 (blue: included; dark grey: insufficient data) mm200_share20 Measure Value Included area 187,803 km² (16.6% of Ethiopia) Agreement with EMI-implied membership No reference registered Domain files NetCDF · GeoJSON outline Unknown area 4 km² Baseline 1981-2010 unavailable: 12 of 30 years are not in the data (1981-1992); the period is not shortened. Baseline 1991-2020 unavailable: 2 of 30 years are not in the data (1991-1992); the period is not shortened. Baseline 1996-2025 +2,541 km² / −1,530 km²
Share of each EMI rainfall region included Region Included I Northeast 0% II Northwest 0% III Southwest 14.3% IV Central 0% V East 2.3% VI South Highland 69.3% VII South 95.1% VIII South-Southeast lowlands 14.1%
Candidate mm200_share30 (blue: included; dark grey: insufficient data) mm200_share30 Measure Value Included area 75,625 km² (6.7% of Ethiopia) Agreement with EMI-implied membership No reference registered Domain files NetCDF · GeoJSON outline Unknown area 4 km² Baseline 1981-2010 unavailable: 12 of 30 years are not in the data (1981-1992); the period is not shortened. Baseline 1991-2020 unavailable: 2 of 30 years are not in the data (1991-1992); the period is not shortened. Baseline 1996-2025 +6,370 km² / −1,533 km²
Share of each EMI rainfall region included Region Included I Northeast 0% II Northwest 0% III Southwest 0% IV Central 0% V East 0% VI South Highland 23.1% VII South 10.5% VIII South-Southeast lowlands 13.9%
Candidate mm200_share40 (blue: included; dark grey: insufficient data) mm200_share40 Measure Value Included area 4,363 km² (0.4% of Ethiopia) Agreement with EMI-implied membership No reference registered Domain files NetCDF · GeoJSON outline Unknown area 4 km² Baseline 1981-2010 unavailable: 12 of 30 years are not in the data (1981-1992); the period is not shortened. Baseline 1991-2020 unavailable: 2 of 30 years are not in the data (1991-1992); the period is not shortened. Baseline 1996-2025 +999 km² / −0 km²
Share of each EMI rainfall region included Region Included I Northeast 0% II Northwest 0% III Southwest 0% IV Central 0% V East 0% VI South Highland 0% VII South 0% VIII South-Southeast lowlands 1.3%
r3_regime_rule (blue: included; dark grey: insufficient data) r3_regime_rule Measure Value Included area 433,264 km² (38.3% of Ethiopia) Agreement with EMI-implied membership Regime membership is not an amount/share threshold. Domain files NetCDF · GeoJSON outline
Share of each EMI rainfall region included Region Included I Northeast 0% II Northwest 0% III Southwest 0% IV Central 0% V East 11.7% VI South Highland 66.5% VII South 70.6% VIII South-Southeast lowlands 96.4%
earlier_mm120_share20 (blue: included; dark grey: insufficient data) earlier_mm120_share20 Measure Value Included area 367,718 km² (32.5% of Ethiopia) Agreement with EMI-implied membership Not an amount/share threshold rule. Domain files NetCDF · GeoJSON outline
Share of each EMI rainfall region included Region Included I Northeast 0% II Northwest 0% III Southwest 9% IV Central 0% V East 6.2% VI South Highland 77.7% VII South 98.5% VIII South-Southeast lowlands 66.6%
share40_mm60 (blue: included; dark grey: insufficient data) share40_mm60 Measure Value Included area 145,332 km² (12.9% of Ethiopia) Agreement with EMI-implied membership Not an amount/share threshold rule. Domain files NetCDF · GeoJSON outline
Share of each EMI rainfall region included Region Included I Northeast 0% II Northwest 0% III Southwest 0% IV Central 0% V East 0% VI South Highland 0% VII South 0% VIII South-Southeast lowlands 44%
wettest_mm60 (blue: included; dark grey: insufficient data) wettest_mm60 Measure Value Included area 400,042 km² (35.4% of Ethiopia) Agreement with EMI-implied membership Not an amount/share threshold rule. Domain files NetCDF · GeoJSON outline
Share of each EMI rainfall region included Region Included I Northeast 2% II Northwest 0% III Southwest 0% IV Central 0% V East 16.4% VI South Highland 62.3% VII South 61.6% VIII South-Southeast lowlands 86.5%
Named comparisons Rule Share of Ethiopia Agreement with EMI-implied membership Files Current ONDJ R3 (Deyr) rainfall domain: R3 membership, ONDJ >= 30 mm, patches < 3 cells removed 38.3% Regime membership is not an amount/share threshold. NetCDF · GeoJSON Earlier ONDJ rainfall domain (not in use): ONDJ >= 120 mm and >= 20% of annual (1993-2024) 32.5% Not an amount/share threshold rule. NetCDF · GeoJSON 40% contribution rule: ONDJ >= 40% of annual and >= 60 mm (no cleanup) 12.9% Not an amount/share threshold rule. NetCDF · GeoJSON Wettest-season rule: ONDJ wetter than FMAM and JJAS, >= 60 mm (no cleanup) 35.4% Not an amount/share threshold rule. NetCDF · GeoJSON
Named comparisons side by side All threshold candidates (rows: rainfall cutoff; columns: share cutoff) Included share of Ethiopia for each candidate How many candidates include each cell Regional inclusion by candidate Agreement of CHIRPS with the EMI classes Reference Mode Exact class Within one class CHIRPS wetter / drier Outside the class interval (median / 90th pct) Comparable / uncertain area
Largest changes between neighbouring cutoffs From To Changed Area switching mm30_share10 mm30_share20 annual share percent 379,994 km² mm120_share10 mm200_share10 seasonal rainfall mm 343,668 km² mm60_share10 mm60_share20 annual share percent 329,609 km² mm120_share10 mm120_share20 annual share percent 235,458 km² mm120_share20 mm200_share20 seasonal rainfall mm 219,809 km² mm120_share30 mm200_share30 seasonal rainfall mm 201,533 km²
Baseline sensitivity of mm30_share10 Candidates nested (raising a cutoff never adds a cell): yes. Dataset sensitivity: not assessed (CHIRPS only).
