Hilo, HI weather in September
September in Hilo: warm and humid, with rain on most days. Highs 83°F, lows 70°F, rain on about 23 days. Keep rain gear handy.
- Normal high
- 83°F
- Normal low
- 70°F
- Wet days
- 23
- 8.7 in total
- Muggy days
- 27
- dew point 65°F+
How September changes from start to finish
| September 1 | September 30 | |
|---|---|---|
| Normal high | 83°F | 83°F |
| Normal low | 70°F | 70°F |
| Chance of a wet day | 81% | 76% |
| Sunrise / sunset | 6:04 am / 6:35 pm | 6:10 am / 6:09 pm |
| Daylight | 12.5 h | 12.0 h |
Chance of a wet day: average for the first and last 7 days of the month. Times are local clock time (Hawaii time (no daylight saving)).
A typical September day
- 6 am71°Fdew point 66°F
- 9 am79°Fdew point 69°F
- Noon82°Fdew point 70°F
- 3 pm82°Fdew point 70°F
- 6 pm78°Fdew point 69°F
- 9 pm74°Fdew point 69°F
NOAA hourly normals (local standard time) from Hilo Intl Airport (2 mi away); average wind 6 mph.
What kind of days to expect
- Comfortable dayshigh 65-80°F and dew point under 60°F0 of 30
- Beach dayshigh 80-95°F, under 0.05 in of rain, afternoon wind under 15 mph11 of 30
- Hot dayshigh 90°F or more1 of 30
- Muggy daysdaily mean dew point 65°F or more27 of 30
- Wet daysat least 0.01 in of rain or melted snow23 of 30
- Notable rainat least 0.10 in15 of 30
- Freezing nightslow 32°F or below0 of 30
Average days per September, counted from daily records for each year 1991-2020.
Rain in September
Normal precipitation is 8.7 in; a dry September brings about 4.9 in and a wet one about 9.4 in (25th and 75th percentiles). About 5 days bring half an inch or more, and about 2 an inch or more.
How September varies from year to year
- Warmest September, 1991-20202014: average high 88°F
- Coolest September1999: average high 81°F
- Wettest September2015: 25.0 in
- Driest September2010: 2.8 in
- Highest reading93°F (September 2, 2015)
- Lowest reading63°F (September 15, 2009)
From the station's daily records with NOAA quality flags removed; most recent date shown when a reading repeats.
September compared with August and October
| August | September | October | |
|---|---|---|---|
| Normal high | 83°F | 83°F | 82°F |
| Normal low | 70°F | 70°F | 69°F |
| Wet days | 27 | 23 | 23 |
| Comfortable days | 0 | 0 | 0 |
| Daylight | 12.8 h | 12.3 h | 11.7 h |
Highs change by 0°F from August and -1°F into October.
Nearby alternatives in September
- Warmer: Kihei, HI114 mi · high 90°F · 5 wet days
- Drier: Kailua-Kona, HI59 mi · high 87°F · 6 wet days
How Hilo ranks in September
- Normal high159th warmest of 378 cities; 7th of 7 in Hawaii
- Wet days378th driest of 378
- Comfortable days339th most of 342
What to pack for Hilo in September
- A rain jacket or umbrella – rain on about 23 days
- A swimsuit – about 11 beach days
Heating and cooling
September has 0 heating degree days and 347 cooling degree days (base 65°F), 11% of the year's total heating and cooling demand.
Questions
How hot is Hilo in September?
The normal high is 83°F and the normal low is 70°F. From 1991 to 2020 the hottest September reading was 93°F (most recently on September 2, 2015).
Does it rain a lot in Hilo in September?
About 23 days in September have at least 0.01 in of precipitation, and the normal total is 8.7 in. The wettest September in 1991-2020 was in 2015 (25.0 in); the driest was in 2010 (2.8 in).
Is September a good time to visit Hilo?
September ranks 9th of 12 months on our comfort score for Hilo (40 out of 100). It has almost no comfortable days and about 1 day at 90°F or hotter. The best months are January and February.
Where the numbers come from
- Temperature, rain, frost dates and humidity and wind by hour: Hilo Intl Airport (USW00021504), 2.2 mi E of the city center, 38 ft . NOAA normals and daily records, 1991-2020.
- Snowfall and snow depth: Kapoho Beach 93.11 (USC00513368), 23 mi SE of the city center, 20 ft . NOAA normals and daily records, 1991-2020.
- Daily humidity and wind: Hilo International Airport (912850-21504), 2.5 mi E of the city center, 29 ft . Hourly observations, 1991-2020.
- Not available for this location: cloud cover (no station close enough or similar enough in elevation).