Running Weather Today (Sun., Sept. 13): Chicago 64°F and Dry, New York Under a Flood Watch, Austin's Heat Index to 109°F
Quick answer — Chicago is the one city on this board with a genuinely good Sunday long-run window: 64°F at Midway at 6:25 a.m. over a 54°F dew point, with a north wind near 10 mph and no rain until about 1 p.m. New York and Boston are both under Flood Watches, and Manhattan had a Flood Advisory running until 8:15 a.m. Austin starts at 79°F with a 76°F dew point and turns into a Heat Advisory at noon.
Where can you run this morning without getting soaked or cooked?
| City | Latest NWS reading | 7 a.m. forecast (temp / dew) | Wind | Rain chance |
|---|---|---|---|---|
| Chicago | 64°F, dew 54°F (Midway, 6:25 a.m. CDT) | 66°F / 55°F | NNW 10 mph, gusts to 25 later | 1% until noon, 40% after 1 p.m. |
| Los Angeles | Grid forecast only this morning | 67°F / 64°F, cloudy | Calm | 0% |
| Boston | 66°F, cloudy (Logan, 7:20 a.m.) | 64°F / 61°F | S 7 mph | 16% at 7, 74% at 10, 100% at 11 |
| New York | 68°F, dew 68°F, 100% humidity (Central Park, 6:51 a.m.) | 70°F / 70°F, storms | E 3 mph | 87–88% until 11 a.m. |
| Austin | 79°F, dew 76°F, heat index 83°F (Camp Mabry, 6:09 a.m. CDT) | 79°F / 76°F | S 5 mph | 2% |
Is Chicago really the pick on a Sunday this wet?
Yes, and by more than the temperature suggests. A 54°F dew point sits below the level where most runners feel humidity at all. The catch is the wind: an out-and-back on the Lakefront Trail runs into it on the way home if you start south, so go north first and let it push you back. Singlet and shorts. Anyone doing a 20-miler in a fall marathon build should take this window, because Saturday's board had Chicago at a 66°F dew point.
| Chicago | NWS forecast |
|---|---|
| Dew point, all morning | 54–57°F |
| Wind | North, 10 mph |
| High | 72°F |
| Afternoon | Back to about 68°F, showers after 1 p.m. |
How bad is the rain in New York until noon?
Bad enough to change the route. Central Park reads 68°F with the dew point equal to the temperature, which is fog-and-drizzle air even between storms. Treadmill, or wait. If you do go out early, stay off low paths along the rivers and anything near a storm drain.
| New York | NWS detail |
|---|---|
| Flood Watch (NWS Upton) | All five boroughs, southern Westchester and northeast New Jersey until noon; 1–2 in. of rain, locally around 3 |
| Rain already down | 0.5–1.5 in. on radar at 6:16 a.m. |
| Flood Advisory | Manhattan, Hudson, Bergen, Essex and Passaic counties, to 8:15 a.m. |
| Storm chance | Near 88% through 10 a.m., 38% at 11, 5% at 2 p.m. |
| 2 p.m. | 78°F over a 71°F dew point: dry but heavy |
Why is Boston's window closing at 10 a.m.?
Because the storm chances step up almost hour by hour, under a Flood Watch for Suffolk and Norfolk counties that runs until 6 p.m. A 6-mile run on the Esplanade that ends by 9 a.m. is fine. Anything longer is a gamble with lightning, not just water.
| Boston (NWS Boston/Norton) | Forecast |
|---|---|
| 7 a.m. | Slight chance of showers, dew point 61°F |
| 9 a.m. | 33% chance of storms |
| 10 a.m. | 74% |
| 11 a.m.–2 p.m. | 100%, dew point 66°F by 11 |
| Rain totals | Widespread 0.5–2 in.; narrow bands of 2–4 in. within three hours |
What should you wear in each city?
| City | Wear | Leave home |
|---|---|---|
| Chicago | Singlet, split shorts, a cap for the north wind on the return | Any long sleeve |
| Los Angeles | Singlet and short shorts before 9 a.m.; 75°F at 10 and 85°F by noon | Dark colors after 10 |
| Boston | Tank, shorts, a thin shell you can tie off; done by 9 | Cotton socks |
| New York | If you must: brimmed cap, bright top, anti-chafe on every seam | Headphones near flooded crossings |
| Austin | Lightest singlet you own, handheld bottle, finish by 9 | A hat that traps heat — use a visor |
At 70°F with the dew point at 70°F, every stitch you wear stays wet for the entire run, so fabric choice decides whether you chafe. Our temperature chart already moves you a band warmer above a 65°F dew point. One budget option we would put on a wet, gray morning is Bubblelime's racerback tank in red, $9: a nylon-spandex blend that sheds water better than cotton and shows up in low light, but it is a tight fit that clings when soaked. Price and stock from bubblelime.com, checked Sept. 13 at 9:54 p.m. ET: $9, with only XS and M left.
How long do Austin runners have before the Heat Advisory?
About three hours of tolerable air, and it is tolerable only by Texas standards. An after-dark run is no escape either, so a dawn loop on the Butler Trail around Lady Bird Lake is the only sensible slot.
| Austin (NWS Austin/San Antonio) | Forecast |
|---|---|
| Heat Advisory | I-35 corridor, noon to 7 p.m., heat index up to 109°F (issued 6:09 a.m. CDT) |
| 8 a.m. | 80°F |
| 10 a.m. | 86°F |
| Noon | 93°F |
| 4 p.m. | 100°F, on the way to a high near 101°F |
| Tonight | Low 79°F, evening heat index near 105°F |
What did the Erie Marathon get at the 7 a.m. gun?
Almost exactly what the forecast promised on Thursday. Our Erie preview called it a sticky morning on a flat course, and that is what the runners are in now. Everything else that raced this weekend is in the Sept. 12–13 race list.
| Erie | Reading |
|---|---|
| Airport station, 6:51 a.m. | 69°F, dew point 68°F, 96% humidity, light southwest breeze |
| 8 a.m. (NWS Cleveland grid) | Patchy fog |
| 10 a.m. | 73°F |
| 11 a.m., back of the pack on Presque Isle | 75°F over a 70°F dew point |
Where do next weekend's races stand?
Saturday, Sept. 19 enters the National Weather Service seven-day grid today. We added the first read for the Air Force Marathon, Top of Utah and the other Saturday starts to next week's race list. First-timers racing that weekend should read the race-morning checklist this week, and anyone starting before sunrise in Dayton will want the dark-start gear notes. Every daily board lands on the weather page.
TL;DR
| City | Call |
|---|---|
| Chicago | 64°F over 54°F dew, north wind — go long before 1 p.m. |
| Los Angeles | 67°F and gray; out by 9, before 85°F at noon |
| Boston | Short run done by 9; storms and a Flood Watch to 6 p.m. |
| New York | Flood Watch to noon, 1–3 in. of rain; run after 2 p.m. or inside |
| Austin | 79°F over 76°F dew at dawn; Heat Advisory noon–7, heat index to 109°F |
Sources
- Hourly temperature, dew point, wind, sky and rain chance: National Weather Service gridpoint forecasts for Central Park (OKX), Boston (BOX), Grant Park Chicago (LOT), downtown Los Angeles (LOX), Austin (EWX) and Presque Isle, Erie (CLE), retrieved Sept. 13, 2026, 7:42 a.m. ET.
- Current conditions: NWS station observations at Central Park (KNYC), Boston Logan (KBOS), Chicago Midway (KMDW), Austin Camp Mabry (KATT) and Erie International (KERI), latest reports before 7:30 a.m. ET.
- Watches and advisories: NWS active alerts — Flood Watch and Flood Advisory from NWS Upton (2:07 a.m. and 6:16 a.m. EDT), Flood Watch from NWS Boston/Norton (1:57 a.m. EDT), Heat Advisory from NWS Austin/San Antonio (6:09 a.m. CDT), all Sept. 13.