What the Organisers Announced, and When
The warnings started a week out. At race pack collection on the weekend of 19 September, the organisers posted notices saying they were watching NEA's 24-hour PSI and one-hour PM2.5 readings [1]. The day before the race they told participants that changes might be needed, citing action thresholds in their contingency plan and in SportSG and NEA guidance [2].
The central region's 24-hour PSI entered the unhealthy range, which starts at 101, at 8pm on Saturday 26 September, when it reached 104 [3]. When the organisers reviewed the readings at 2am it stood at 126 in the central region, 109 in the east and 104 in the west [3][4], above their thresholds. At about 3am Decathlon and MetaSport announced the changes on social media and by email and text message to participants [2].
The 21.1 km was cut to 10 km, dropping the planned loop past Marina Bay Sands, the ArtScience Museum, the Singapore Flyer, Gardens by the Bay and Marina Barrage; the 10 km, 5 km and 670 m Kids Dash kept their distances [3]. Start times stayed the same, every category became non-competitive with no official rankings, and the awards ceremony was cancelled [3]. The organisers said the changes were meant to reduce prolonged, strenuous exertion while still letting participants take part safely [5].
The Air and the Weather on Race Morning
The 24-hour PSI kept rising through the race. In the central region, which takes in the Kallang venue [2], it was 127 at 5am, 128 at 7am and 129 at 8am; in the east it went from 113 to 116 over the same hours [4]. Because it averages the previous 24 hours, it lagged the air runners were actually breathing. The one-hour PM2.5 reading in the central region fell from 127 micrograms per cubic metre at 2am to 62 at 4am and 52 at 5am, and stayed between 54 and 64 until 8am [6].
That matches what runners saw. One half-marathon entrant said the haze had "pretty much cleared up" by the start, even though the PSI was high [2]. Changi Airport, about 14 km east of the start, still reported haze all morning, with visibility of 4 km at 5am and 3 km by 7.30am [7].
The heat was a normal Singapore early morning. Changi recorded 28°C, a 23°C dew point and 74% humidity at 5am, with a 2-knot wind, then 27°C at 6am and 26°C to 27°C from 6.30am to 8am, with humidity of 79% to 84% [8]. A dew point of 23°C to 24°C already makes for heavy air to run in, before any haze.
The Course: What Was Planned, and What Was Run
All three road races started on Nicoll Highway beside the National Stadium, entered through a pre-start area on Mountbatten Road, and finished at Decathlon Singapore Lab [9]. The planned half marathon ran along the Kallang Basin, onto Sheares Avenue and past Marina Bay Sands, the ArtScience Museum, the Singapore Flyer, Gardens by the Bay and Marina Barrage [10], then back through Tanjong Rhu to the finish [9]. The organiser promoted it as a course of wide roads and sweeping curves rather than sharp turns [10].
Nicoll Highway was closed to traffic from 1am to 9am. On Sheares Avenue, Marina Gardens Drive and Tanjong Rhu Road only one or two lanes were closed, so parts of the planned half ran beside open lanes [9].
The plan had eight aid stations on the half, at 2.8, 4.9, 7.3, 9.8, 12.2, 14, 16.5 and 19 km, all with water and all but the first with 100PLUS, and an SiS energy gel at 12.2 km [9]. Cut-offs were set at 11.7 km by 7.20am and 19.1 km by 8.35am, based on 10 minutes per kilometre from the last wave; slower runners were to be sent on a shortcut to the finish and listed as DNF [9]. The 10 km had water at 2.8, 4.8 and 7.1 km and a 4.5 km cut-off at 7.05am [9].
What was run instead was a 10 km loop through Kallang [5]. The results show timing points at 2.5, 5, 6.5 and 10 km for the shortened race and at 2.5, 5, 6.6 and 10 km for the regular 10 km [11], which points to the two following much the same route. The full half-marathon course has not yet been raced.
What Runners Got, and What They Said
A large crowd still turned up for the shortened half [2]. One 19-year-old in it received a medal and the finisher T-shirt, which the runner said felt "undeserved", but took the day as a fun run, enjoyed the course and set a 10 km best [2]. Another runner, 26, said 10 km was just a normal run and the half had been the goal with colleagues, and added that the organisers kept reminding runners at the start to watch how they felt [2]. On Instagram, one entrant posted a 10 km personal best and praised the race atmosphere [12].
Most public reaction backed the call. Pacers from the Singapore Runners Club and many participants thanked the organisers for putting health first, one calling it "the responsible thing to do" [2][5]. Others were less sure: one asked what difference running 10 km rather than 21 km made in the haze [12], and a forum commenter questioned holding a race in the haze season at all [13].
The sore point is money. Half-marathon places cost S$78 at the super early bird rate and S$98 at the end of registration, against S$60 to S$86 for the 10 km [2][14]. Under the terms, fees are not refunded if the event is changed or cancelled unless the organisers say otherwise, and the organisers may change the race for haze [3]. Runners asked about refunds under the race-day announcement, and by the time of reporting no refund, credit or other compensation had been offered [2][5]. The two runners interviewed on race day hoped for a refund, or failing that a discount on next year's race [2].
How Fast the Field Was
The organisers said there would be no official rankings, but the timing company posted results with splits [11]. They list 3,496 finishers in the shortened half from 4,392 entries. The fastest man ran 36:21 and the fastest woman 39:39, and the average finish was 1:02:40 [15]. Tenth place was 38:20 for men and 45:16 for women [11].
The regular 10 km had 1,863 finishers from 2,250 entries, with fastest times of 36:42 for men and 42:55 for women and tenth places of 39:56 and 49:41 [11][15]. The 5 km had 1,238 finishers from 1,526 entries, with fastest times of 17:16 and 19:18 [15].
The timing data show the front of the shortened half crossing the start line at about 5.14am, a few minutes after the planned 5.10am first wave [9][11].
Race-Morning Logistics
Trains do not run before the half-marathon and 10 km starts, so the organisers ran shuttle buses from 20 MRT stations, boarding from 3.10am to 3.35am for the half, with a wristband needed to board [9]. Taxis could drop off at Stadium MRT and the Stadium Drive coach bay [9]. The pre-start area on Mountbatten Road opened at 4am and the start pens at 4.40am, and runners were asked to arrive 30 minutes before their start [9].
Bag deposit was a paid add-on: bags handed in at the start were moved to the Festival Village at the finish [9]. Entries received after 30 August got bibs without the runner's name [9]. The race pack for the half, 10 km and 5 km held a race tee, socks, a cap and a drawstring bag [9], and the listed entry fees are before GST [14].
Should You Enter the 2027 Race?
Yes, if you want a Singapore half marathon of about 4,400 entries on mostly closed central roads, with shuttle buses for the early start and aid stations 1.8 to 2.8 km apart on the planned half. In their first year the organisers set haze thresholds in advance and told runners of the change about two hours before the start.
Think twice if a refund matters to you. Late September brought haze in 2026, the terms let the organisers change the race without refunds, and none was offered for the cut half. If you enter, read the terms on changes first, and watch NEA's readings in the week before.
No date for a second edition had been announced by 29 September 2026, and the full half-marathon course has still never been raced.
Nobody from this site ran the race. This review draws on the organiser's runners' guide, the published results, official air-quality readings, airport weather records, Singapore news reports, and runners' comments to reporters, on social media and in a forum.