Croatia
Istria in September: weather, sea & travel advice
This month's data profile
Rain shapes the decision
Istria in September is climatically well suited to city breaks, family holidays, beach holidays and active holidays and hiking. The average daily high is around 23 °C, and the sea is about 23 °C. With about 11 rainy days it is wet.
Historical monthly averages, not a weather forecast. Individual days and years can differ substantially.
Rank among 12 monthly averages
79/100 · #4
Warmth
#4
Dryness
#8
Sun
#6
Sea warmth
#3
Published best categories: Overall, Beach, City break, Active, Family
Istria · SeptemberPhoto: Einaz80 · CC BY-SA 4.0Climate facts
- Average high
- 23 °C
- Average low
- 17 °C
- Sea
- 23 °C
- Rainy days (est.)
- 11 rainy days (est.)
- Sun (est.)
- 5 h/day
- Humidity
- 71 %
Climate evidence with direct month comparison
The highlighted row is the selected month. Precipitation total and rainy days are separate monthly averages.
| Month | Avg high °C | Avg low °C | Rainy days (est.) | Precipitation mm | Sun h/day (est.) | Humidity % | Wind m/s | Sea °C | Score |
|---|---|---|---|---|---|---|---|---|---|
| August | 28 | 21 | 9 | 67 | 7.1 | 65 | 2.6 | 25 | 85 |
| September (selected) | 23 | 17 | 11 | 110 | 5.1 | 71 | 3.1 | 23 | 79 |
| October | 18 | 13 | 11 | 109 | 3.2 | 78 | 3.5 | 20 | 59 |
How do the previous and next months compare?
Baseline: September (79/100)
Positive and negative values show the change from the selected month.
| Score Δ | Average high Δ | Average low Δ | Rainy days Δ | Rain Δ | Sun Δ | Humidity Δ | Wind Δ | Sea Δ | |
|---|---|---|---|---|---|---|---|---|---|
| August | +6 | +4.7 °C | +3.9 °C | -2.1 | -43.7 mm | +2 h | -6 % | -0.5 m/s | +2.6 °C |
| October | -20 | -4.7 °C | -4 °C | +0.3 | -1.3 mm | -1.9 h | +6.9 % | +0.3 m/s | -2.9 °C |
All twelve months in context
Find a place to stay
Where to stay in Istria
Compare available stays, prices and cancellation terms for Istria on Booking.com.
Booking.comFind places to stayAffiliate link: there is no extra cost to you.
Useful next decisions
Frequently asked questions
How warm is Istria in September?
The average daily high is around 23 °C, with an average daily low of about 17 °C.
Can you swim in Istria in September?
The sea is about 23 °C (swimmable).
Does it rain a lot in Istria in September?
The curated estimate is about 11 rainy days per month, not a directly measured long-term average. Total precipitation averages around 110 mm for the month. A rainy day does not mean all-day rain.
When is the best time to visit Istria?
By the climate score, June, July, August and September are the strongest months for Istria. For a beach trip: June, July, August and September. September is one of them.