Late-September Tasman System
2 resorts in the path, 37cm at the biggest. Likely — the models agree on this one.
+37CM
Predicted at Whakapapa
21–63cm across the models
Storm
Sep 25–29
2 resorts in the path
Peak
Sep 27
26cm at Whakapapa
Predicted
37cm
Whakapapa · 21–63cm across the models
Confidence
Likely
Updated
Sep 21, 18:30 UTC
SnowSure Forecaster
Written from the blend and the model spread · updated Sep 21, 18:30 UTC
Current prediction: 21–63cm for Whakapapa between 2026-09-25 and 2026-09-29, 37cm our central figure. The biggest day is 2026-09-27 at 26cm. Also in the path: Tūroa 37cm. Confidence is likely: the models agree on both the window and the magnitude. On day one we said 45cm for Whakapapa; that is the number we are measured against. These figures are re-read from the latest model blend; each entry in the log keeps what we said at the time.
Forecast log
Every entry, newest first. Nothing is overwritten.
- Day 3·Sep 21·Likely·41cm(-9)
Late-September Tasman System: 41–40cm for Whakapapa and Tūroa
Day 3: totals down 8.6cm since the previous entry, but the window remains unchanged. For the upcoming storm window from 2026-09-25 to 2026-09-29, we are now predicting 41.2cm for Whakapapa and 40.7cm for Tūroa. The biggest day is expected to be 2026-09-27, with Whakapapa seeing 29.5cm and Tūroa 28.4cm. Confidence in these totals is likely, and the trend is strengthening as we approach the event. We will continue to monitor the models for any shifts in timing or amounts.
Window Sep 25–29 · Whakapapa
- Day 2·Sep 20·Likely·50cm(+5)
Late-September Tasman System: 49.6–49.8cm for Tūroa and Whakapapa
Day 2: totals up 4.6cm since the previous entry, with the window holding. For the upcoming storm window from 2026-09-25 to 2026-09-29, we are now predicting 49.8cm for Tūroa and 49.6cm for Whakapapa. The biggest day is expected to be 2026-09-27, with Tūroa seeing 18.3cm and Whakapapa potentially reaching 20.6cm. Confidence remains likely, and the trend is strengthening for both resorts. As we approach the event, we will continue to monitor model outputs for any shifts in timing or totals.
Window Sep 25–29 · Tūroa
- Day 1·Sep 19·Likely·45cmFirst prediction
Late-September Tasman System: 45–95.6cm for Whakapapa
The prediction for the window from 2026-09-25 to 2026-09-29 indicates Whakapapa could see 45.2cm, with a range of 9–95.6cm, while Tūroa may receive 40.4cm, ranging from 1.1–84.7cm. Current patterns suggest a weakening trend, which may impact snowfall totals. Among the resorts, Whakapapa appears to have a more favorable outlook, likely to receive the most significant totals, particularly on 2026-09-27 with a peak of 29.5cm. Tūroa's confidence remains lower as we continue to monitor the situation. A shift in the overall weather pattern could change these predictions significantly.
Window Sep 25–29 · Whakapapa
Snow by day
Sep 24 – Sep 30, with a day either side. For each resort: where the freeze line sits against the mountain, then what falls — snow in cm, rain in mm — and the day read from those two numbers.
Whakapapabase 1,630 m · summit 2,300 m
37cm snow
Modelled at the summit, 2,300 m · snow to the base
linem
/ raincm · mm
Thu
Sep 24
Dry
Fri
Sep 25
Snow
Sat
Sep 26
Snow
Sun
Sep 27
Snow
Mon
Sep 28
Snow
Tue
Sep 29
Snow
Wed
Sep 30
Snow
snow every day
Tūroabase 1,600 m · summit 2,322 m
37cm snow
Modelled at the summit, 2,322 m · snow to the base
linem
/ raincm · mm
Thu
Sep 24
Dry
Fri
Sep 25
Snow
Sat
Sep 26
Snow
Sun
Sep 27
Snow
Mon
Sep 28
Snow
Tue
Sep 29
Snow
Wed
Sep 30
Snow
snow every day
snowrain low, snow highraindryThe dots are the freeze line — the height where rain turns to snow. Solid: straight from the models. Hollow: estimated from temperature. Above the summit line it rains on the whole mountain; below the base line it snows all the way down. Blue bars are snow in cm, amber bars rain in mm; the totals above are their sums.
Rain / snow line
Base to summit for each mountain, with the snow line cut across them.
The system
700mb flow — where the storm is, and what is steering it. Pins sized by forecast total.
72-hour snowfall forecast for the same window.
In the path
Forecast, not observation — none of this has fallen yet. Totals are across the window. We will post what fell when the window closes.
Last updated 2026-09-21 18:30 UTC. SnowSure scans a blend of seven weather models twice daily and flags systems clearing 30cm over 72 hours, three to fourteen days out. This watch opened on 2026-09-19 with 35cm forecast at Whakapapa.
