When can you paint outdoors?
Finland's short summer means the outdoor painting season lasts only 4–5 months. Timing is everything: a surface painted too early suffers from cold nights, while a project started too late risks getting cut short by autumn rains. This guide walks you through month by month when each surface type becomes paintable.
All thresholds are based on paint manufacturer (Tikkurila, Teknos, Cello, Uula) guidelines and our weather assessment. Always check real-time conditions on maalataanko.fi before picking up the brush.
Weather requirements by surface type
Different surfaces require different conditions. Here's a summary:
- Wood (exterior walls): minimum +5 °C, below 80% humidity, 24 h rain-free, wind under 8 m/s
- Masonry (plaster, concrete): minimum +8 °C, below 75% humidity, 24 h rain-free
- Metal (metal roof, railing): minimum +10 °C, below 70% humidity, 12 h rain-free
- Deck and floor: minimum +5 °C, below 80% humidity, 48 h rain-free
Note that deck paints require the longest rain-free window (48 h) because horizontal surfaces are most exposed to rain. Metal surfaces require the highest temperature (+10 °C).
Painting calendar month by month
April — preparation begins
In April, night frosts are still common and the ground may be wet from snowmelt. Painting is usually not possible, but preparation work can start: washing, scraping, sanding, and masking. Check the condition of paints and tools.
In southern Finland, temperatures in late April often reach +8–12 °C during the day, but overnight temperatures typically remain below +5 °C.
May — wood surfaces become viable
May is the real start of the painting season in southern Finland. Average temperatures exceed +10 °C and overnight lows mostly stay above +5 °C. Wood surface painting is possible from mid-May — provided the forecast shows no overnight frost.
In northern Finland and Lapland, May is still too early. Overnight temperatures are often +0…+5 °C and the ground may be wet. Wait until June.
- Wood: possible in southern Finland from mid-May
- Masonry: limited — requires +8 °C, usually only late in the month
- Metal: not recommended — overnight temperatures rarely above +10 °C
- Deck: limited — the long rain-free requirement (48h) is hard to meet in spring weather
June — the season opens for all surfaces
June is the most reliable start month. Daytime temperatures are typically +15–22 °C and overnight lows above +10 °C across most of the country. Humidity is low and dry spells are common.
In June, all surface types are paintable everywhere in Finland — including Lapland and the coast. This is the best month to start a major painting project.
- Wood: excellent
- Masonry: excellent
- Metal: good — dew point may be close in the morning, paint around midday
- Deck: good — dry spells make the 48 h rain-free window achievable
July — the best month
July is statistically Finland's warmest month. Daytime temperatures of +20–25 °C and warm nights. This is the best month for painting everywhere in Finland.
Warning: July also brings thunderstorms and heavy showers. Monitor the forecast and be prepared for breaks. Extreme heat (above +25 °C) can also be harmful — direct sunshine dries paint too quickly.
- Wood: excellent
- Masonry: excellent
- Metal: excellent
- Deck: excellent
August — good but more humid
August is still warm, but humidity rises and rain becomes more frequent towards the end of the month. Painting works well, but drying times increase compared to June–July.
Monitor humidity closely. Above 70% combined with below +15 °C slows drying significantly.
- Wood: good
- Masonry: good — the humidity limit (75%) is reached more easily
- Metal: good
- Deck: limited — 48 h rain-free harder to achieve
September — last chances
September is the painting season's final month. In southern Finland, daytime temperatures are +12–16 °C and overnight lows approach +5 °C. Wood surface painting is possible in early September, but the window narrows quickly.
In Lapland, September is practically too late for all surface painting. Night frosts can begin as early as the start of September.
- Wood: possible (early September, southern Finland)
- Masonry: limited — overnight temperatures often below +8 °C
- Metal: not recommended — temperature rarely sufficient
- Deck: not recommended — humidity and rain prevent drying
October–March — no painting
From October to March, outdoor painting is not possible. Temperatures are too low, humidity too high, and days too short for proper drying. Use winter for planning: choose paints, calculate material and cost estimates, and order paint early before the spring rush.
Regional differences
Finland is a long country — from Helsinki to Utsjoki is over 1,100 km. The painting season's start and end varies significantly:
- Southern Finland (Helsinki, Turku, Tampere): season from mid-May to mid-September — about 4 months
- Central Finland (Jyväskylä, Kuopio): season from early June to early September — about 3 months
- Northern Finland and Lapland (Oulu, Rovaniemi, Sodankylä): season from mid-June to late August — about 2.5 months
The difference between south and north is typically 2–3 weeks. In Lapland, night frosts can return as early as late August, shortening the season further.
Reading a weather forecast for painting
A weather forecast tells a lot, but a painter needs to read it correctly. The key parameters to watch:
- Temperature (°C): check both daytime and overnight temperature. Paint continues drying at night — if the temperature drops below the surface-specific minimum, drying stalls.
- Humidity (%): high humidity slows drying. Mornings and evenings have the highest humidity. The best painting time is 10:00–16:00.
- Dew point: the paint surface temperature must be at least 3 °C above the dew point. If the dew point is close to the air temperature, the air is too humid.
- Rain: check the rain forecast for the entire drying period — 24 h for wood, 48 h for decks. Even light rain (below 0.5 mm) can damage fresh paint.
- Wind: under 8 m/s is ideal. Strong wind dries paint too quickly, creates an uneven finish, and carries dust and debris.
maalataanko.fi combines all these parameters into one clear assessment. Select your location and surface type — the service shows whether painting is safe over the next 48 hours.
Summary: when to paint what?
Here's a quick summary of the painting season in southern Finland:
- Wood surfaces: mid-May – mid-September
- Masonry surfaces: June – late August
- Metal surfaces: June – August
- Deck: June – mid-August
In Lapland, shorten each period by 2–3 weeks.
Find more information in our guides:
- Outdoor painting fundamentals — weather requirements, prep work, and manufacturer instructions
- Painting in sunshine — challenges and solutions in hot weather
- Metal roof painting — special requirements for metal surfaces
- Deck painting and treatment — deck's long drying time and treatment options
- House painting step by step — complete guide for wooden houses