January in Postojna Cave — the hardest end of the year
Hardest · 2.6/10January averages 0°C (32°F), cold enough that sightseeing works in bursts rather than in one long day on foot.
At 114 mm this is a genuinely wet month: about 0 sunny days in total, and outdoor plans need an indoor fallback.
It scores 2.6/10 here, 11th of 12 months, against 8.4/10 in the destination's best month.
Expect mid-season pricing, and crowds are light for this destination.
Pack insulated layers, a windproof shell, gloves and boots with grip, a proper rain shell rather than an umbrella, footwear you can get muddy.
If your dates are flexible, June is materially better in Postojna Cave — 5.8 points higher on the same scale.
February in Postojna Cave — the hardest end of the year
Hardest · 4.1/10February averages 3°C (37°F), cold enough that sightseeing works in bursts rather than in one long day on foot.
Rainfall runs 58 mm, so plan one flexible day in three; you still get about 0 sunny days and 10.1 hours of daylight.
It scores 4.1/10 here, 9th of 12 months, against 8.4/10 in the destination's best month.
Expect mid-season pricing, and crowds are light for this destination.
Pack insulated layers, a windproof shell, gloves and boots with grip, a packable rain layer, footwear you can get muddy.
If your dates are flexible, June is materially better in Postojna Cave — 4.3 points higher on the same scale.
March in Postojna Cave — workable with trade-offs
Trade-offs · 5.6/10March averages 5°C (41°F) — jacket weather. Comfortable for walking and museums, too cool for anything water-based.
Rainfall runs 90 mm, so plan one flexible day in three; you still get about 9 sunny days and 11.6 hours of daylight.
It scores 5.6/10 here, 7th of 12 months, against 8.4/10 in the destination's best month.
Expect mid-season pricing, and crowds are moderate.
Pack a mid-weight jacket, long sleeves and shoes you can walk 15 km in, a packable rain layer, footwear you can get muddy.
If your dates are flexible, June is materially better in Postojna Cave — 2.8 points higher on the same scale.
April in Postojna Cave — reliably good (5th best month)
Good · 7.3/10April averages 8°C (47°F) — jacket weather. Comfortable for walking and museums, too cool for anything water-based.
Rainfall runs 95 mm, so plan one flexible day in three; you still get about 17 sunny days and 13.3 hours of daylight.
It scores 7.3/10 here, 5th of 12 months, against 8.4/10 in the destination's best month.
Expect mid-season pricing, and crowds are moderate.
Pack a mid-weight jacket, long sleeves and shoes you can walk 15 km in, a packable rain layer, footwear you can get muddy.
May in Postojna Cave — reliably good (4th best month)
Good · 7.7/10May averages 14°C (57°F), the range most people find easiest for walking a city all day without either overheating or losing daylight to weather.
At 167 mm this is a genuinely wet month: about 21 sunny days in total, and outdoor plans need an indoor fallback.
It scores 7.7/10 here, 4th of 12 months, against 8.4/10 in the destination's best month.
Expect mid-season pricing, and crowds are moderate.
Pack layers you can shed by midday plus one warm layer for the evening, a proper rain shell rather than an umbrella, footwear you can get muddy.
June in Postojna Cave — the year's strongest window
Best window · 8.4/10June averages 19°C (66°F), the range most people find easiest for walking a city all day without either overheating or losing daylight to weather.
At 109 mm this is a genuinely wet month: about 30 sunny days in total, and outdoor plans need an indoor fallback.
On our climate-comfort scale this is the top-ranked month of the year for Postojna Cave at 8.4/10 — the reference point every other month on this page is measured against.
Expect mid-season pricing, and crowds are moderate.
Pack layers you can shed by midday plus one warm layer for the evening, a proper rain shell rather than an umbrella, footwear you can get muddy.
July in Postojna Cave — reliably good (2nd best month)
Good · 8.3/10July averages 21°C (70°F) — warm enough for beach and boat plans, still short of the heat that pushes sightseeing into early morning.
At 136 mm this is a genuinely wet month: about 31 sunny days in total, and outdoor plans need an indoor fallback.
It scores 8.3/10 here, 2nd of 12 months, against 8.4/10 in the destination's best month.
Expect peak pricing, and this is one of the busiest months here. You are paying the year's highest rates for the year's best conditions — book early or shift a few weeks either side.
Pack light clothing, swimwear and real sun protection, a proper rain shell rather than an umbrella, footwear you can get muddy.
August in Postojna Cave — reliably good (3rd best month)
Good · 8.3/10August averages 21°C (70°F) — warm enough for beach and boat plans, still short of the heat that pushes sightseeing into early morning.
At 139 mm this is a genuinely wet month: about 24 sunny days in total, and outdoor plans need an indoor fallback.
It scores 8.3/10 here, 3rd of 12 months, against 8.4/10 in the destination's best month.
Expect peak pricing, and this is one of the busiest months here. You are paying the year's highest rates for the year's best conditions — book early or shift a few weeks either side.
Pack light clothing, swimwear and real sun protection, a proper rain shell rather than an umbrella, footwear you can get muddy.
September in Postojna Cave — workable with trade-offs
Trade-offs · 6.2/10September averages 16°C (60°F), the range most people find easiest for walking a city all day without either overheating or losing daylight to weather.
220 mm of rain puts this in monsoon territory — about 11 sunny days across the whole month, and multi-day washouts are normal.
It scores 6.2/10 here, 6th of 12 months, against 8.4/10 in the destination's best month.
Expect mid-season pricing, and crowds are moderate.
Pack layers you can shed by midday plus one warm layer for the evening, a proper rain shell rather than an umbrella, footwear you can get muddy.
If your dates are flexible, June is materially better in Postojna Cave — 2.2 points higher on the same scale.
October in Postojna Cave — the hardest end of the year
Hardest · 4.9/10October averages 13°C (55°F), the range most people find easiest for walking a city all day without either overheating or losing daylight to weather.
At 167 mm this is a genuinely wet month: about 2 sunny days in total, and outdoor plans need an indoor fallback.
It scores 4.9/10 here, 8th of 12 months, against 8.4/10 in the destination's best month.
Expect mid-season pricing, and crowds are light for this destination.
Pack layers you can shed by midday plus one warm layer for the evening, a proper rain shell rather than an umbrella, footwear you can get muddy.
If your dates are flexible, June is materially better in Postojna Cave — 3.5 points higher on the same scale.
November in Postojna Cave — the hardest end of the year
Hardest · 3.4/10November averages 5°C (41°F) — jacket weather. Comfortable for walking and museums, too cool for anything water-based.
At 127 mm this is a genuinely wet month: about 0 sunny days in total, and outdoor plans need an indoor fallback.
It scores 3.4/10 here, 10th of 12 months, against 8.4/10 in the destination's best month.
Expect low-season pricing, and crowds are light for this destination.
Pack a mid-weight jacket, long sleeves and shoes you can walk 15 km in, a proper rain shell rather than an umbrella, footwear you can get muddy.
If your dates are flexible, June is materially better in Postojna Cave — 5 points higher on the same scale.
December in Postojna Cave — the hardest end of the year
Hardest · 2.5/10December averages 1°C (35°F), cold enough that sightseeing works in bursts rather than in one long day on foot.
At 128 mm this is a genuinely wet month: about 0 sunny days in total, and outdoor plans need an indoor fallback.
It scores 2.5/10 here, 12th of 12 months, against 8.4/10 in the destination's best month.
Expect mid-season pricing, and crowds are light for this destination.
Pack insulated layers, a windproof shell, gloves and boots with grip, a proper rain shell rather than an umbrella, footwear you can get muddy.
If your dates are flexible, June is materially better in Postojna Cave — 5.9 points higher on the same scale.
