Quick take: Aim for dry, mild days.. ideally 15–25 °C with humidity under 70 %.. and you'll get a coat that cures hard and keeps its colour.
Why timing matters
Paint needs the right combo of temperature, humidity and UV to cure. Too cold and it stays soft; too hot and it skins over before it bonds. New Zealand's wild micro-climates mean the "right time" shifts by region.
North Island vs. South Island cheat-sheet
| Region | Prime Painting Window | Notes |
|---|---|---|
| Northland & Auckland | Sept – May | Sub-tropical showers.. watch the hourly forecast. |
| Waikato & Bay of Plenty | Oct – Apr | High humidity.. paint late morning once dew burns off. |
| Wellington & Kapiti | Nov – Mar | Northerlies can dust-blast wet paint.. set wind breaks. |
| Christchurch & Canterbury | Oct – Mar | Dry nor'wester helps cure but plan around nor'easter drizzle. |
| Otago & Queenstown Lakes | Dec – Feb | Alpine nights drop below 10 °C till late spring.. use fast-curing paints outside this window. |
Temp & humidity rules of thumb
- Daytime high ≥ 15 °C for at least four hours after you finish a coat.
- Overnight low ≥ 10 °C to avoid condensation blooming the film.
- Relative humidity < 70 %.. check your phone's weather app.
- Surface must be dry (a dry footpath is a good proxy).
Can you paint in winter?
Yes.. if you must. Use cold-cure acrylics rated to 5 °C, start after the frost lifts, and finish by 2 pm so the film skins before dusk. Expect longer re-coat times.
Pro tips for a bulletproof finish
- Log the forecast: MetService's hourly graph is your best mate.
- Start on the shady side: Follow the sun to avoid blistering.
- Mind the dew: Stop two hours before sunset when temperatures dip.
- Store paint indoors overnight: Keeps viscosity consistent.
- Add 5 % water on hot days: Slows flash-off (always follow spec sheet).
FAQs
How long after rain can I paint?
When the surface is bone-dry.. typically 24 hours of clear weather. Timber weatherboards may need longer.
What's the maximum temperature?
Most exterior acrylics top out at 30 °C; darker colours absorb heat faster, so aim for < 25 °C.
Do I need to reschedule if humidity spikes midday?
Not usually.. humidity rises as paint dries. Just ensure the first hour after application meets the < 70 % rule.
Need help nailing the timing? Click below for a free consultation.. Daniel will eyeball your forecast and give honest advice.
