Hilo weather in September: Hilo, Hawaii: normal highs, lows, rain and records for September
Hilo in September has a normal high of 83°F and a normal low of 70°F, a daily mean of 77°F, holding near 83°F all month. Measurable precipitation falls on 23 days in a normal September, 8.70 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 29°C and low of 21°C, 221 mm of precipitation in September.
- NOAA stationHilo International Airport 87
- Station IDUSW00021504
- Location19.72°N 155.05°W
- Elevation38 ft (12 m)
- Population (census place)48,223
- Jan 79° 64°
- Feb 78° 64°
- Mar 79° 65°
- Apr 79° 66°
- May 81° 67°
- Jun 82° 69°
- Jul 83° 70°
- Aug 83° 70°
- Sep 83° 70°
- Oct 82° 69°
- Nov 80° 68°
- Dec 79° 66°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Hilo in September?
The normal high is 83°F and the normal low 70°F, for a daily mean of 76.5°F. September is 0.1°F cooler than August and 0.8°F warmer than October. September is the 2nd warmest month of the year in Hilo and the 9th wettest. From one year to the next September's mean temperature typically moves about 1.3°F either way (NOAA's standard deviation), so roughly two Septembers in three average between 75°F and 78°F.
Bars above: each day's normal high to low. Columns below: the chance of 0.01 inch or more of precipitation that day, on a scale of 0 to 100% (highest 82%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| September 1 | 83°F | 70°F | 82% | 55% |
| September 8 | 83°F | 70°F | 80% | 53% |
| September 15 | 83°F | 70°F | 78% | 52% |
| September 22 | 83°F | 70°F | 77% | 52% |
| September 30 | 83°F | 70°F | 75% | 52% |
Every day of September: normal high, low and chance of precipitation (warmest afternoon September 14, coldest night September 26)
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in | Daylight |
|---|---|---|---|---|---|
| September 1 | 83°F | 70°F | 82% | 55% | 12 h 30 min |
| September 2 | 83°F | 70°F | 82% | 54% | 12 h 30 min |
| September 3 | 83°F | 70°F | 82% | 54% | 12 h 30 min |
| September 4 | 83°F | 70°F | 81% | 54% | 12 h 30 min |
| September 5 | 83°F | 70°F | 81% | 54% | 12 h 30 min |
| September 6 | 83°F | 70°F | 81% | 54% | 12 h 30 min |
| September 7 | 83°F | 70°F | 81% | 53% | 12 h 30 min |
| September 8 | 83°F | 70°F | 80% | 53% | 12 h 20 min |
| September 9 | 83°F | 70°F | 80% | 53% | 12 h 20 min |
| September 10 | 83°F | 70°F | 80% | 53% | 12 h 20 min |
| September 11 | 83°F | 70°F | 79% | 53% | 12 h 20 min |
| September 12 | 83°F | 70°F | 79% | 53% | 12 h 20 min |
| September 13 | 83°F | 70°F | 79% | 53% | 12 h 20 min |
| September 14 | 83°F | 70°F | 79% | 53% | 12 h 20 min |
| September 15 | 83°F | 70°F | 78% | 52% | 12 h 20 min |
| September 16 | 83°F | 70°F | 78% | 52% | 12 h 20 min |
| September 17 | 83°F | 70°F | 78% | 52% | 12 h 10 min |
| September 18 | 83°F | 70°F | 78% | 52% | 12 h 10 min |
| September 19 | 83°F | 70°F | 77% | 52% | 12 h 10 min |
| September 20 | 83°F | 70°F | 77% | 52% | 12 h 10 min |
| September 21 | 83°F | 70°F | 77% | 52% | 12 h 10 min |
| September 22 | 83°F | 70°F | 77% | 52% | 12 h 10 min |
| September 23 | 83°F | 70°F | 77% | 52% | 12 h 10 min |
| September 24 | 83°F | 70°F | 76% | 52% | 12 h 10 min |
| September 25 | 83°F | 70°F | 76% | 52% | 12 h 10 min |
| September 26 | 83°F | 70°F | 76% | 52% | 12 h |
| September 27 | 83°F | 70°F | 76% | 52% | 12 h |
| September 28 | 83°F | 70°F | 76% | 52% | 12 h |
| September 29 | 83°F | 70°F | 75% | 52% | 12 h |
| September 30 | 83°F | 70°F | 75% | 52% | 12 h |
- Normal high
- 83°FSeptember average
- Normal low
- 70°FSeptember average
- Precipitation
- 8.70 inmonth total
- Days with precipitation
- 230.01 inch or more
- Days at 90°F or more
- 1
- Daylight
- 12 h 30 min to 12 hSeptember 1 to September 30
- Days at 70°F or more
- 30
- Days at 80°F or more
- 29
- Sunshine
- 75%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00021504; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in Hilo in September?
On a given September day the chance of 0.01 inch or more is 78% on average, highest around September 1 (82%). In all, 8.70 in falls on 23 days of a normal September, 2 of them with an inch or more.
In a normal September in Hilo, 1 days reach 90°F.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00021504.
How humid and windy is Hilo in September?
At 3 p.m. the normal temperature is 82°F with 67% relative humidity and a dew point of 70°F; at 6 a.m. it is 70°F with 83% humidity. The wind averages 6.2 mph, most often from the east-northeast in the afternoon. A dew point of 65°F or more feels muggy to most people.
| Time | Temperature | Dew point | Humidity | Wind | Clear or few clouds |
|---|---|---|---|---|---|
| 6 a.m. | 70°F | 65°F | 83% | 5.6 mph | 27% |
| 9 a.m. | 79°F | 69°F | 72% | 5.2 mph | 24% |
| noon | 82°F | 70°F | 66% | 8.6 mph | 31% |
| 3 p.m. | 82°F | 70°F | 67% | 9.2 mph | 24% |
| 6 p.m. | 78°F | 69°F | 76% | 5.4 mph | 27% |
| 9 p.m. | 74°F | 69°F | 85% | 4.9 mph | 23% |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00021504. Hourly normals exist only for NOAA's first-order stations; a dash where NOAA publishes no value for that hour (the sky at some hours).
What are the records for September in Hilo?
The warmest September temperature on Hilo's official record (since 1949) is 93°F, on September 26, 2014; the coldest is 61°F, on September 30, 1970. The wettest September brought 25.03 in (2015).
The September mean against the 1991-2020 normal of 76.5°F: 2021 77.0°F (+0.5), 2022 77.1°F (+0.6), 2023 77.2°F (+0.7), 2024 77.0°F (+0.5), 2025 77.4°F (+0.9), 2026 77.8°F (+1.3). 6 of 6 ran warmer than normal.
| September | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 77.0°F | +0.5°F | 8.94 in |
| 2022 | 77.1°F | +0.6°F | 4.84 in |
| 2023 | 77.2°F | +0.7°F | 5.67 in |
| 2024 | 77.0°F | +0.5°F | 6.75 in |
| 2025 | 77.4°F | +0.9°F | 2.76 in |
| 2026 | 77.8°F | +1.3°F | 16.19 in |
Source: records: ACIS, NWS threaded record ITOthr; recent months: ACIS, station USW00021504. Records and recent months use complete months only.
How does September in Hilo compare across Hawaii?
Across the 18 places PlainClimate covers in Hawaii, September normal highs run from 75°F in Kula to 90°F in Kahului; Hilo's is 83°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.