The system in six readings September is running wet so far.
September is running wet so far.
And the week ahead keeps it coming.
What just fell, what just left the tap, and what the sky is bringing next — read in pairs, as cause and effect.
01 Supply — What came in
01 Rainfall · September · 3 stations · as of 2026-09-14
Wetter than a
typical September so far.
1.6× normal so far
this September so far
typical first 14 days of September
Theewaterskloof 40mm · 2.4×
Voëlvlei 21mm · 1.2×
Wemmershoek 34mm · 0.7×
Verdict Ahead of what a typical September brings in its first 14 days.
02 Storage · 6 dams combined
The dams slipped —
0.6 points off.
75% was 76% last week
Verdict Comfortable, even with the slip.
02 Demand — What went out
03 Daily demand · vs target
The city is using
less than expected.
855Mℓ 5 Mℓ under target
Verdict 1% below the daily target — the kind of week that buys headroom.
04 Per person · ℓ/day · 12-mo avg
14 litres less,
per Capetonian.
146ℓ/day −14 ℓ vs trailing avg
Trailing 12-month average
Verdict A small but real saving — sustained, this is what shaves a percentage point off summer drawdown.
03 Forecast — What's coming next
05 Forecast · 7 days · 6 catchments
3.7 times a typical
week of rain.
3.7× normal
vs the same 7 calendar days averaged across the past 10 years
Verdict Wed looks like the wettest day.
06 Where it lands · per catchment
Each dam, and
what's coming for it.
3.7× a typical week
total forecast across the six catchments vs the same 7 calendar days over the past 10 years, weighted by dam size
Theewaterskloof 76%
+43mm 4.6× normal
Voëlvlei 59%
+31mm 3.4× normal
Berg River 91%
+60mm 3.1× normal
Wemmershoek 89%
+56mm 2.7× normal
Steenbras Upper 84%
+44mm 2.7× normal
Steenbras Lower 48%
+45mm 2.9× normal
Verdict Berg River (91% full) and Wemmershoek (89% full) get the biggest soaking.
