Best time to visit Piran

Re-score for me — drag the dial — every chart recolours live for your heat & sea limits 27°C · sea 29°C
I'm comfortable up to 27°C feels-like
22° heat-averse 30° heat-loving

Default 27 °C is the upper edge of the Holiday Climate Index "ideal comfort" band (Scott, Rutty, Amelung & Tang, 2016). Above this, most warm-tourism travellers report measurable discomfort.

Sea feels bathtub at 29°C
26° strict 31° tolerant

Default 29 °C is the Beach Climate Index "bathtub" line (Morgan et al.) — where the sea stops being refreshing and starts feeling like a warm bath.

Saved to this browser. Changes update the strips below.
Sea temp cold <18° chilly 18–21° ideal 22–26° warm 27–28° bathtub 29–30° too warm ≥31°
Recent · 2020-2024
Interest Google Trends 2021-2025 searches, not arrivals (?)
Sea Nov 2022 – Dec 2024 (?)
Day · avg daily high (?)
Night · avg overnight low (?)
UV index · On a typical day around midday, UV is about this (?)
123457764211
On the sunniest 1 in 10 days, UV reaches this — and even higher
467864
PM2.5 air quality · on a typical day (?)
131812989787101014
On the worst 1 in 10 days, PM2.5 reaches this — and even higher
254022151213121411192027
June 9/10 feels 26°C (+1°C vs 1991-2020) · HCI 90/100
Day 26° · Night 19° 64% humidity 18 km/h wind 8 rain days (81h) 295h sun sea 23°C
Thermal 8
Sky 10
Rain 8
Wind 10

Higher = better, including rain & wind (green = "doesn't hurt the score", not "lots of it").

How is this scored? HCI / Steadman / CCI gate — full methodology and citations below.

Compare with another destination

Add as many as you like — stacked below the main strips above. Each row is just the recent-window score strip and (for beach destinations) sea-temperature strip.

Tours in Piran

6 top-rated tours via Viator. Booking links earn this site a commission at no cost to you. Map locations are approximate (centred on Piran).

  1. 1Shore Excursion/Private Tour - Lake Bled and Ljubljana from Koper4.89★ (36)8hfrom $735
  2. 2Piran Old Town Walking Tour4.91★ (11)from $87
  3. 3Shore Excursion/Private - Postojna Cave and Ljubljana from Koper5.00★ (4)from $673
  4. 4Transfer to Venice area - Private & Relaxed Experience5.00★ (1)from $290
  5. 5Customized Slovenian Adventure from Koper or Piran5.00★ (1)6hfrom $904
  6. 6Private Piran Walking Tour (tasting of local wine & products included)4.89★ (9)1h 30mfrom $231

Last refreshed 2026-06-24.

Similar climatesPortorož100% · Rovinj98% · Pula97%

Other destinations with the most-alike year-round climate to Piran (apparent temperature, rain hours, sunshine — matched within the same trip-profile). The ±N chip compares each match's typical score for the current month against Piran's. Based on the 2020-2024 climatology, not this year's actual weather.

Month-by-month

Month Temp °C Feels °C Rain days Rain h Rain h/day Humidity Wind km/h Sun h UV Interest Score
Jan 3–9 6 8 111 13.9 74% 18 146 1 Quiet 6
Feb 4–11 8 7 85 12.1 75% 18 161 2 Quiet 7
Mar 6–13 10 7 85 12.1 66% 20 218 3 Quiet 8
Apr 9–16 13 8 80 10.0 63% 20 240 4 Quiet 8
May 14–21 20 14 137 9.8 68% 20 271 5 Quiet 7
Jun 19–26 26 8 81 10.1 64% 18 295 7 Quiet 9
Jul 21–29 30 8 49 6.1 57% 18 309 7 Quiet 8
Aug 21–29 30 8 65 8.1 57% 18 284 6 Peak 8
Sep 17–24 24 10 109 10.9 61% 19 231 4 Quiet 8
Oct 14–20 19 11 135 12.3 72% 19 191 2 Quiet 7
Nov 9–14 12 10 114 11.4 71% 20 149 1 Moderate 7
Dec 6–11 8 13 178 13.7 75% 19 113 1 Quiet 5

UV Index in Piran by Month

UV index in Piran peaks at 7 (high) in July, dropping to 1 (low) in January. June, July, August have high UV — SPF 30+ and sunglasses recommended.

Best months in detail

June

9/10

19–26°C · 8 rain days (81h) · 295 sun hours · 64% humidity · Quiet crowd · UV 7 (high)

April

8/10

9–16°C (feels 13°C) · 8 rain days (80h) · 240 sun hours · 63% humidity · Quiet crowd · UV 4 (moderate) · sunniest 1 in 10 days reach 6 (moderate)

September

8/10

17–24°C · 10 rain days (109h) · 231 sun hours · 61% humidity · Quiet crowd · UV 4 (moderate) · sunniest 1 in 10 days reach 6 (moderate)

Every month

Show the other 9 months in detail

January

6/10

3–9°C (feels 6°C) · 8 rain days (111h) · 146 sun hours · 74% humidity · Quiet crowd · UV 1 (low)

February

7/10

4–11°C (feels 8°C) · 7 rain days (85h) · 161 sun hours · 75% humidity · Quiet crowd · UV 2 (low)

March

8/10

6–13°C (feels 10°C) · 7 rain days (85h) · 218 sun hours · 66% humidity · Quiet crowd · UV 3 (low) · sunniest 1 in 10 days reach 4 (moderate)

May

7/10

14–21°C · 14 rain days (137h) · 271 sun hours · 68% humidity · Quiet crowd · UV 5 (moderate) · sunniest 1 in 10 days reach 7 (high)

July

8/10

21–29°C (feels 30°C) · 8 rain days (49h) · 309 sun hours · 57% humidity · Quiet crowd · UV 7 (high) · sunniest 1 in 10 days reach 8 (very high)

August

8/10

21–29°C (feels 30°C) · 8 rain days (65h) · 284 sun hours · 57% humidity · Peak crowd · UV 6 (high)

October

7/10

14–20°C · 11 rain days (135h) · 191 sun hours · 72% humidity · Quiet crowd · UV 2 (low) · sunniest 1 in 10 days reach 4 (moderate)

November

7/10

9–14°C (feels 12°C) · 10 rain days (114h) · 149 sun hours · 71% humidity · Moderate crowd · UV 1 (low)

December

5/10

6–11°C (feels 8°C) · 13 rain days (178h) · 113 sun hours · 75% humidity · Quiet crowd · UV 1 (low)

Frequently asked questions about visiting Piran

When is the best time to visit Piran?

June is the highest-scoring month (9/10 on the Holiday Climate Index). Typical conditions: 19–26°C (8 rainy days). The top three months by score are June, April, September.

What is the worst time to visit Piran?

December is the lowest-scoring month (5/10). Typical conditions: 6–11°C (13 rainy days).

Is Piran too hot in summer?

2 months (July, August) trip the heat deal-breaker in our scoring: apparent temperature crosses the comfort cap, so even with clear skies and low rain the score is held down. Plan around it if heat tolerance is low.

When are crowds lowest in Piran?

Search-interest seasonality (Google Trends 2021-2025) is lowest in January and peaks in August. Interest tracks both in-trip visitors and lead-time planners, so treat it as a "destination is on people's minds" signal rather than literal arrivals.

Which months in Piran have good weather but fewer tourists?

June (climate 9/10, crowd index 0) and March (climate 8/10, crowd index 0) — shoulder months with above-average climate and below-median search-interest. Often the best value-for-weather trade.

What is the UV index in Piran by month?

UV peaks at 7 (high) in July and is lowest in January at 1 (low). Monthly peak values: Jan 1, Feb 2, Mar 3, Apr 4, May 5, Jun 7, Jul 7, Aug 6, Sep 4, Oct 2, Nov 1, Dec 1.

What is the UV index in Piran in July?

July is the peak UV month in Piran, with a daily-peak UV index of 7 (high). Apply SPF 30+, wear sunglasses, and seek shade during midday hours.

How high can UV get in Piran on the sunniest days?

Most days look like the monthly average, but on the sunniest ~1 in 10 days UV climbs higher than the mean suggests. July is the worst case: typical days average UV 7 (high), but the top 10% of days reach UV 8 (very high) — and even higher. Months where the sunniest days routinely exceed the typical reading: March, April, May, July, September, October. Plan sun protection for the worst case, not the average.

Is air quality in Piran bad for travelers?

PM2.5 (fine-particle pollution) exceeds the WHO sensitive-group guideline (15 µg/m³) in 6 months: January, February, March, October, November, December. The worst month is February with a typical-day mean of 18 µg/m³ (unhealthy for sensitive); on the worst 10% of days PM2.5 reaches 40 µg/m³ (hazardous) and higher. People with asthma, heart conditions, or sensitive children may want to avoid these months or limit outdoor activity. Source: CAMS via Open-Meteo.