It's mid-September. You're out the door at six for a long one. Fourteen degrees, bit of a breeze off the water, definitely still jumper weather. The sunnies stay on the bench by the door, because it doesn't feel like a sunglasses day.
Ninety minutes later you're squinting into a sun sitting a lot higher than it was when you left, you've got a dull ache starting behind your eyes, and tomorrow they'll feel like someone's tipped sand in them.
Here's the bit most people never join up: the temperature had nothing to do with it.
UV doesn't care how cold you are
ARPANSA - the federal body that actually measures this stuff - states it flatly: solar UV levels are generally not related to temperature. There can be high UV on cool days. The heat you feel is infrared. The damage you don't feel is ultraviolet. They're different parts of the spectrum and they arrive on different schedules.
What actually drives UV is how high the sun sits in the sky, and spring is the season it climbs back. The air takes months to catch up - oceans and land are slow to warm, which is why February is hotter than December even though the sun peaks in December. So for the whole back half of the year's build-up, you get a sun angle that's heading toward summer while the temperature is still telling you it's fine.
That gap is spring. And that gap is where Australians get caught, because most of us run our sun protection off how hot it feels rather than what the sun's actually doing.
The Cancer Council's line is that sun protection is recommended whenever the UV index hits 3 or above. Across most of the country, a clear September midday clears 3 without trying, and by October a good chunk of Australia is sitting in the high single digits at lunchtime while the air is still a comfortable 22.
The second spring problem: the sun's in your face, not above you
The other thing that changes right now is when you're training. Once daylight saving kicks in on the first Sunday of October across NSW, Victoria, SA, Tassie and the ACT, evening sessions move into the light and morning sessions start earlier - and both of those windows put the sun low and flat, straight down the road at you.
Low sun is a different problem to overhead sun. Overhead, a decent lens does the work. Low and flat, light arrives from the side and from underneath, around the edge of the frame rather than through the lens. This is the season where coverage and wrap matter more than how dark the tint is, and where a pair that sits too far off your face gives you a bright stripe of glare along the bottom of your vision for the whole run.
Worth saying plainly: squinting is not protection. It cuts glare, which makes you more comfortable. It does nothing about UV. Plenty of people get through spring squinting and assume they've handled it.
What to actually look for, in order
1. UV400, and don't negotiate on it. Tint darkness and UV protection are two separate specifications. A dark lens with no UV filtering is worse than no sunglasses at all, because your pupil opens up behind the dark tint and lets more UV through to the retina. UV400 means the lens blocks wavelengths up to 400nm, which covers UVA and UVB. Over years, the thing you're protecting against is pterygium, cataract and photokeratitis - none of which announce themselves on the day.
2. Understand what the lens category is telling you. AS/NZS 1067 is the Australian and New Zealand standard, and it sorts lenses 0 to 4 based on how much visible light gets through - not how much UV they block. Category 3 runs roughly 8-18% light transmission and is the workhorse for Australian daylight. Category 4 is alpine and desert territory and isn't legal for driving. Categories 0 and 1 aren't really sunglasses. If you want the full breakdown, we've written it up in Cat 2 vs Cat 3 vs Cat 4 explained.
3. Coverage and fit, weighted for the low-sun window. Spring also brings back the sweat you haven't dealt with since March. A frame that stayed put through winter cross-country might start walking down your nose on the first warm tempo run. Grip on the nose and temples does more than clamping pressure - if you need to check yours, start with running sunglasses that don't bounce.
4. Polarisation, applied with judgement. It's genuinely good for wet spring roads, water, and the glare off car bonnets in traffic. It's less good when you're reading a bike computer or phone screen, or picking icy patches on an early alpine ride. We covered the honest version in when polarised lenses help and when they get in your way.
Do the ten-minute spring reset
Before the season properly turns, get your existing pair sorted. Rinse them under a tap before you wipe them - spring grit plus a dry cloth is how lenses get scratched. Sunscreen on the lens is the other spring special; it smears, it's mildly corrosive to coatings, and it turns into a haze you'll blame on the lens quality. Check the nose grips haven't gone hard and glazed, because that's usually what's behind a pair that suddenly won't stay put. Full method is in how to clean and care for running sunglasses.
If the reset tells you the pair's had it, the spec sheet to match is straightforward. Our RYZE Glacier sits at 17% VLT - Category 3, polarised, UV400 - which is the range that handles a low October sun and a high December one without you owning two pairs. If you're on the bike, where wind and side glare do most of the damage, SHYFT Glacier is the same build with a taller lens and a fuller wrap. Both $100.
The short version
Spring UV is a real number that has nothing to do with the temperature you're dressing for. The sun is already climbing, the air hasn't caught up, and your training has just moved into the low-light windows at both ends of the day. Take the sunnies. It's a cool morning, not a safe one.