Het weer in Hervey Bay in september

Early September is peak whale season in Hervey Bay - the last two weeks of August and the first week of September are when the bay is busiest with humpbacks - and the forum's warning is about what comes immediately after. Past that first week, northerlies become more likely, and they make the bay choppy enough to cancel trips and occasionally ground the whole fleet for a day or two. Whale tours and Fraser Island trips both book out days ahead in this stretch, so it is a month to arrange before arriving rather than on the day. The record: 25.3C days that feel like 26C, 13.5C nights, 2.2 precipitation days carrying 21.6mm, 10.4 hours of sun and a 22C sea.

Regulars are specific this falls within the local summer, running December through February, hot and humid with tropical showers a genuine possibility even on an otherwise sunny stretch. Our row backs that hot, genuinely wet read, 29.9C reading as a hot 33C, over 21C nights feeling 23C, with a substantial 120.2mm of rain across 7 days and humidity at 73 percent. Regulars are consistent nearby Lady Elliot Island's turtle nesting season runs through this month as one of three annually, a real seasonal draw for anyone basing a trip around wildlife. Genuinely warm enough for long swims throughout, tropical downpours aside. The sea sits at a warm, swimmable 27C. The record: 11.2 hours of sun, a 16.5 kph wind and AQI 27.

Regulars are specific about how the whale season winds down: boats generally finish by the long weekend in early October, and by then the bay mostly holds mothers and calves rather than the bigger, more active groups of August and September - the calves themselves, though, are described as bolder and more curious, often approaching boats directly. Regulars also flag a weather-driven risk this late in the season - once past early September, northerly winds pick up more often, making the bay choppy enough to cancel trips on a bad day. Our row backs a settled, mild spring, 27.1C over 17.1C nights, with 98.4mm of rain across 6.4 days and a moderate 16.1 kph wind. The sea holds 23.8C. The record: humidity 73 percent, 10.6 hours of sun and AQI 34.

November is the closing edge of the whale season and regulars are precise about how thin the edge is. The season is quoted as mid-July to mid-November, they have seen whales in the bay as late as the 10th of November, and yet the last weekend in October is what most of them treat as the real end. By late November they are gone. So a trip booked for the whales works in the first week and is a gamble in the second, and after that it is a beach town rather than a wildlife one. The weather is moving the other way: 28.7C days over 19.3C nights with a 25.2C sea. Our 99.1mm falls across just 6.2 days, sixteen millimetres apiece, so the rain here arrives in bursts. The record: humidity 71 percent, 11.2 hours of sun and AQI 30.

April and May are two of the four months regulars name for K'gari, with October and November - the island is at its best now, and our row agrees: 27.5C over 17.8C, only 4.8 precipitation days, a 25.1C sea and AQI 28. The thing to be clear about is what April does not offer. The humpbacks are still heading north and do not reach Hervey Bay until about mid-July; August is the peak, the season runs into October, and the last fortnight of August into the first week of September is the window for swimming with them, before the northerlies roughen the bay. So this is the month for the island - the lakes, the sand tracks and the rainforest - rather than for the whales. The record: 55.9mm of rain, humidity 73 percent, 9.8 hours of sun and a 15.4 kph wind.