מזג האוויר בזאגרב במאי

May is the month the Zagreb forum recommends for northern Croatia: pleasant temperatures, usually 18 to 25C, and no crowds. Rain is treated as a given rather than a risk - steady through the year here, but only about three inches in the month, which regulars say should not mar a trip. Spring thunderstorms come up often enough that a local answer has hardened around it: they are a regular phenomenon and there is nothing to worry about. A raincoat is the one item posters insist on, and doubly so if Plitvice is on the itinerary, where the water and the mountains knock the temperature down. The record: 22.2C days, 13C nights, 11.8 precipitation days carrying 93.7mm, 10.5 hours of sun and AQI 50.

Regulars are specific that overnight temperatures here typically don't drop below 20C this month, warm enough to walk around comfortably with no sleeves well after dark. Our row backs that hot, genuinely dry read, 29.7C reading as a hot 31C, over 19.1C nights, with rain light at 66.1mm across just 5.5 days and humidity at 68 percent. Regulars are consistent the heat can turn genuinely intense at midday, with some describing streets feeling like they're melting during the hottest stretch, prompting many locals to escape to the coast or nearby mountains rather than stay in the city. Shade, water and pacing outdoor sightseeing around the cooler morning and evening hours are the standard advice. The record: 11.3 hours of sun, an 11.3 kph wind and AQI 49.

Regulars describe this as the month the country's first real summer heat typically lands, often catching visitors still dressed for spring as highs jump quickly from the high teens to 25C-plus within the space of a couple of weeks. Our row backs the warm shift, 28.3C reading as a real 30C, over 18.2C nights, with 78.1mm of rain across 8.2 days - regulars note the swing between years is real too, one describing an extremely hot 30-35C visit while another the year before got rainy, humid weather instead. The practical read is to pack light layers rather than commit fully to summer clothes on the strength of the calendar date alone. The record: humidity 70 percent, 12 hours of sun, a 12.1 kph wind and AQI 54.

Advent here starts the last weekend of November and runs to the middle of January, with events every day rather than only at weekends, and one local calls December their favourite month in the city. Their crowd advice is the first half of the month; it fills as Christmas approaches. On weather they are unromantic - gloomy and wet, or if you are lucky clear and cold - and they tell you not to expect snow. Our row backs both halves: 87 percent humidity with only 4.4 hours of sun inside 8.7 of daylight, 7.2C days that feel like 5C, 1.8C nights that feel like minus 1, and 6.3cm of snow in the whole month. The record: 67.9mm of rain across 6.7 days and AQI 66.

April in Zagreb is pleasant, occasionally rainy and definitively pre-season. Regulars give daily maxima between 12 and 20C with nights of 4 to 9C and about six wet days, against our row's 18.9C, 8.9C and 7.2 precipitation days - and they are firm that early April is not yet the warm part, while May is. What April buys is the country before it fills: the atmosphere is unhurried, the sites are quiet and prices are pre-season. The cost is that some things have not opened yet, since a good many wineries and restaurants run May to October. Swimming is out of the question anywhere in Croatia this month whatever your constitution. The record: feels-like 17C by day and 7C at night, 0.6cm of snow still in the normal and 9.8 hours of sun.