Ann Arbor, Michigan
Mowing
When you can next cut it, and the best slot this weekend.
Current conditions · 1pm, this hour
Prime time
- Grass
- dry
- Ground
- firm
- Rain
- —
- Temp
- 17°
- Wind
- 6 km/h
Forecast for this hour, not a measurement.
Best weekend slot
Saturday 8am–7pm
Verdict: Prime time
temperature — 10°C
Next mow
Now until 7pm
Verdict: Prime time
no rain since Friday, ground firm
The next 10 days
Each row is a day, morning on the left. The more solid a block, the more of the forecast runs agree you can mow. Open a day for the hour-by-hour forecast behind it.
Monday 19 October: 6 hours worth using. Now until 7pm — no rain since Friday, ground firm
Monday 19 October, hour by hour 5am 6am 7am 8am 9am 10am 11am midday 1pm 2pm 3pm 4pm 5pm 6pm 7pm 8pm Chance — — — — — — — — — — — — — — — — Verdict Already gone Already gone Already gone Already gone Already gone Already gone Already gone Already gone Prime time Prime time Prime time Prime time Prime time Prime time dark dark Rainchance · · · · · · · · — — — — — — — — Rainmm · · · · · · · · — — — — — — — — Grass · · · · · · · · dry dry dry dry dry dry dry dry Ground · · · · · · · · firm firm firm firm firm firm firm firm Temp · · · · · · · · 17° 18° 18° 19° 18° 17° 14° 12° Windkm/h · · · · · · · · 6 9 8 8 8 6 5 9 Daylight · · · · · · · · ✓ ✓ ✓ ✓ ✓ ✓ — — Growth: barely growing (growth potential 0.13). Enough to be worth cutting. Growth decides whether a cut is wanted, not how well it will go, so it is not one of the rows above and does not move the chances.
Monday 19 October · now until 7pmConfident
Now until 7pm — no rain since Friday, ground firm
Limiting factor:none
Tuesday 20 October: 11 hours worth using. 8am–7pm — temperature — 10°C
Loading the hour-by-hour forecast…
Growth: barely growing (growth potential 0.20). Enough to be worth cutting. Growth decides whether a cut is wanted, not how well it will go, so it is not one of the rows above and does not move the chances.
Tuesday 20 October · 8am–7pmConfident
8am–7pm — temperature — 10°C
Limiting factor:temperature
Wednesday 21 October: 11 hours worth using. 8am–7pm — temperature — 12°C
Loading the hour-by-hour forecast…
Growth: barely growing (growth potential 0.19). Enough to be worth cutting. Growth decides whether a cut is wanted, not how well it will go, so it is not one of the rows above and does not move the chances.
Wednesday 21 October · 8am–7pmConfident
8am–7pm — temperature — 12°C
Limiting factor:temperature
Thursday 22 October: 11 hours worth using. 8am–7pm — temperature — 13°C
Loading the hour-by-hour forecast…
Growth: growing slowly (growth potential 0.29). Enough to be worth cutting. Growth decides whether a cut is wanted, not how well it will go, so it is not one of the rows above and does not move the chances.
Thursday 22 October · 8am–7pmConfident
8am–7pm — temperature — 13°C
Limiting factor:temperature
Friday 23 October: 11 hours worth using. 8am–7pm — temperature — 10°C
Loading the hour-by-hour forecast…
Growth: growing slowly (growth potential 0.34). Enough to be worth cutting. Growth decides whether a cut is wanted, not how well it will go, so it is not one of the rows above and does not move the chances.
Friday 23 October · 8am–7pmReasonably confident
8am–7pm — temperature — 10°C
Limiting factor:temperature
Saturday 24 October: 11 hours worth using. 8am–7pm — temperature — 10°C
Loading the hour-by-hour forecast…
Growth: growing slowly (growth potential 0.32). Enough to be worth cutting. Growth decides whether a cut is wanted, not how well it will go, so it is not one of the rows above and does not move the chances.
Saturday 24 October · 8am–7pmReasonably confident
8am–7pm — temperature — 10°C
Limiting factor:temperature
Sunday 25 October: 9 hours worth using. 10am–7pm — dry for over a week by then, ground firm
Loading the hour-by-hour forecast…
Growth: growing steadily (growth potential 0.39). Enough to be worth cutting. Growth decides whether a cut is wanted, not how well it will go, so it is not one of the rows above and does not move the chances.
Sunday 25 October · 10am–7pmReasonably confident
10am–7pm — dry for over a week by then, ground firm
Limiting factor:none
Monday 26 October: 10 hours worth using. 9am–7pm — temperature — 11°C
Loading the hour-by-hour forecast…
Growth: growing slowly (growth potential 0.35). Enough to be worth cutting. Growth decides whether a cut is wanted, not how well it will go, so it is not one of the rows above and does not move the chances.
Monday 26 October · 9am–7pmReasonably confident
9am–7pm — temperature — 11°C
Limiting factor:temperature
Tuesday 27 October: 10 hours worth using. 9am–7pm — dry again after a shower, ground firm
Loading the hour-by-hour forecast…
Growth: growing steadily (growth potential 0.44). Enough to be worth cutting. Growth decides whether a cut is wanted, not how well it will go, so it is not one of the rows above and does not move the chances.
Tuesday 27 October · 9am–7pmLow confidence this far out
9am–7pm — dry again after a shower, ground firm
Limiting factor:none
Wednesday 28 October: nothing to cut. Nothing to cut — the grass is barely growing (growth potential 0.03). Conditions themselves are fine.
Loading the hour-by-hour forecast…
Growth: barely growing (growth potential 0.03). Not enough to be worth cutting, which is why no hour is recommended today whatever the weather does.
Wednesday 28 OctoberLow confidence this far out
Nothing to cut — the grass is barely growing (growth potential 0.03). Conditions themselves are fine.
Nothing to cut. The odds below describe the weather only — growth decides whether a cut is wanted, and it is judged separately.
Limiting factor:growth
good to go touch and go dark, frost or snow already goneFainter means fewer forecast runs agree.
Growth
How fast it is growing, and when it will need cutting again.
13%Barely growing
Of the fastest this grass could grow. The turf-industry measure, from today's temperature and day length.
The lawn is barely growing, so it does not need cutting. Leave it — taking leaf off a sward that cannot replace it costs more than it gives.
Held back by both temperature and short days — 10.9 hours of daylight at 10°C.
- Over the next 10 days
- about 9mm of leaf
- Next cut due
- not within the next ten days
This only knows temperature and day length. Feeding, watering, shade and cutting height all move it, so treat it as a rough guide.
Worked out from the PACE Turf growth potential model and day length —how and why.
Seeding
Soil temperature at germination depth, and when the window opens.
Soil temperature in Ann Arbor, Michigan
53°F11.6°C
at 6cm — germination depth
Soil is warming — it should cross 12.5°C in about 7 days, though the forecast doesn't run far enough to confirm it holds.
Warming over the next 10 days.
Cross-checks against an independent estimate from air temperature (10.1°C), which agrees to within 0.6°C.
Most cool-season lawns in the northern US and Canada are bluegrass, tall fescue, or a mix of the two. We assume that, and use 12.5°C as the seeding threshold.
Thresholds for every species
The differences are small. Ryegrass is the quickest off the mark; bluegrass is the slowest and wants the warmest soil. Everything else sits between.
| Species | Soil needed | Days to sprout |
|---|---|---|
| Perennial ryegrass | 8°C | 5–10 |
| Red / chewings fescue | 8–10°C | 10–14 |
| Tall fescuelikely yours | 10–12°C | 10–14 |
| Browntop bentColonial bentgrass | 10–12°C | 14–21 |
| Smooth-stalked meadow grassKentucky bluegrasslikely yours | 12–13°C | 14–28 |
Feeding
Why timing decides whether a feed does anything at all.
Coming in the app
Grass takes up nitrogen when it is growing. Feed a lawn that has stopped and most of it washes past the roots — which is why timing beats product choice.
Right now this lawn is not growing fast enough to make much use of a feed.
The app will work out the actual feeding windows for your lawn — along with weed control, scarifying and moss treatment — and tell you when they open without you having to check.
Ann Arbor, Michigan in detail
Soil temperature in Ann Arbor, Michigan is currently 11.6°C at 6cm, and rising about 5.7°C over the next 10 days. That depth matters because it is where grass seed sits and where roots start working, and it lags air temperature by days — which is why a warm afternoon here tells you very little on its own.
Lawns in this area are typically Kentucky bluegrass with tall fescue, the usual mix for cool-season lawns at this latitude. That blend needs the soil to hold above 12.5°C before seed germinates reliably. Soil is warming — it should cross 12.5°C in about 7 days, though the forecast doesn't run far enough to confirm it holds.
9 of the next 10 days are good mowing days. The best weekend slot right now is Saturday 8am–7pm, on the basis that temperature — 10°C.
The next recommended window in Ann Arbor opens at 1pm on Monday 19 October, and holds while conditions stay put. Underfoot, the ground reads as firm after 8mm rain over the last week, medium (loam) soil.
Save this lawn and we will email you when the windows open.
We already send you the forecast email? Use the same address.
Single-model forecast here — no ensemble covers this location, so there are no odds to show. Forecast from Open-Meteo, refreshed through the day. Soil temperature is modelled, not measured — how that works and where the thresholds come from.