Best time to visit Haleakalā

Re-score for me — drag the dial — every chart on the page recolours live for your heat limit 27°C
I'm comfortable up to 27°C feels-like
22° heat-averse 30° heat-loving

Default 27 °C is the upper edge of the Holiday Climate Index "ideal comfort" band (Scott, Rutty, Amelung & Tang, 2016). Above this, most warm-tourism travellers report measurable discomfort.

Saved to this browser. Changes update the strips below.
Recent · 2020-2024
Interest Google Trends 2021-2025 searches, not arrivals (?)
Day · avg daily high (?)
Night · avg overnight low (?)
UV index · On a typical day around midday, UV is about this (?)
6789910111110865
On the sunniest 1 in 10 days, UV reaches this — and even higher
781011111212116
PM2.5 air quality · on a typical day (?)
576666665555
On the worst 1 in 10 days, PM2.5 reaches this — and even higher
7109899887688
July 4/10 feels 9°C (+2°C vs 1991-2020) · HCI 36/100
Day 10° · Night 3° ☀ UV 10.7 (very high) 72% humidity 7 km/h wind 17 rain days (237h) 295h sun
Thermal 3
Sky 4
Rain 3
Wind 9

Higher = better, including rain & wind (green = "doesn't hurt the score", not "lots of it").

How is this scored? HCI / Steadman / CCI gate — full methodology and citations below.

Compare with another destination

Add as many as you like — stacked below the main strips above. Each row is just the recent-window score strip and (for beach destinations) sea-temperature strip.

Similar climatesPonta Delgada69% · Machu Picchu67% · Acatenango65%

Other destinations with the most-alike year-round climate to Haleakalā (apparent temperature, rain hours, sunshine — matched within the same trip-profile). The ±N chip compares each match's typical score for the current month against Haleakalā's. Based on the 2020-2024 climatology, not this year's actual weather.

Month-by-month

Month Temp °C Feels °C Rain days Rain h Rain h/day Humidity Wind km/h Sun h UV Interest Score
Jan 1–7 5 19 273 14.4 77% 8 232 6 Quiet 2
Feb 0–6 3 21 309 14.7 76% 8 217 7 Quiet 2
Mar 1–7 5 27 396 14.7 78% 8 238 8 Quiet 1
Apr 1–7 5 25 349 14.0 78% 8 251 9 Quiet 1
May 2–8 6 26 352 13.5 78% 8 277 9 Quiet 2
Jun 2–9 7 19 270 14.2 73% 7 287 10 Peak 3
Jul 3–10 9 17 237 13.9 72% 7 295 11 Quiet 4
Aug 3–10 8 23 302 13.1 74% 7 288 11 Quiet 2
Sep 3–10 8 23 298 13.0 75% 7 260 10 Quiet 2
Oct 3–10 8 24 334 13.9 78% 8 251 8 Quiet 2
Nov 2–8 6 20 277 13.8 78% 7 221 6 Quiet 2
Dec 1–7 5 21 280 13.3 79% 8 227 5 Quiet 2

UV Index in Haleakalā by Month

UV index in Haleakalā peaks at 11 (very high) in July, dropping to 5 (moderate) in December. March, April, May, June, July, August, September, October reach very high or extreme levels — apply SPF 50+, wear a hat and protective clothing, and limit direct sun between 11:00 and 17:00.

Best months in detail

July

4/10

3–10°C (feels 9°C) · 17 rain days (237h) · 295 sun hours · 72% humidity · Quiet crowd · UV 11 (very high) · sunniest 1 in 10 days reach 12 (extreme)

June

3/10

2–9°C (feels 7°C) · 19 rain days (270h) · 287 sun hours · 73% humidity · Peak crowd · UV 10 (very high) · sunniest 1 in 10 days reach 11 (extreme)

November

2/10

2–8°C (feels 6°C) · 20 rain days (277h) · 221 sun hours · 78% humidity · Quiet crowd · UV 6 (high)

Every month

Show the other 9 months in detail

January

2/10

1–7°C (feels 5°C) · 19 rain days (273h) · 232 sun hours · 77% humidity · Quiet crowd · UV 6 (moderate) · sunniest 1 in 10 days reach 7 (high)

February

2/10

0–6°C (feels 3°C) · 21 rain days (309h) · 217 sun hours · 76% humidity · Quiet crowd · UV 7 (high) · sunniest 1 in 10 days reach 8 (very high)

March

1/10

1–7°C (feels 5°C) · 27 rain days (396h) · 238 sun hours · 78% humidity · Quiet crowd · UV 8 (very high) · sunniest 1 in 10 days reach 10 (very high)

April

1/10

1–7°C (feels 5°C) · 25 rain days (349h) · 251 sun hours · 78% humidity · Quiet crowd · UV 9 (very high)

May

2/10

2–8°C (feels 6°C) · 26 rain days (352h) · 277 sun hours · 78% humidity · Quiet crowd · UV 9 (very high) · sunniest 1 in 10 days reach 11 (very high)

August

2/10

3–10°C (feels 8°C) · 23 rain days (302h) · 288 sun hours · 74% humidity · Quiet crowd · UV 11 (very high) · sunniest 1 in 10 days reach 12 (extreme)

September

2/10

3–10°C (feels 8°C) · 23 rain days (298h) · 260 sun hours · 75% humidity · Quiet crowd · UV 10 (very high) · sunniest 1 in 10 days reach 11 (extreme)

October

2/10

3–10°C (feels 8°C) · 24 rain days (334h) · 251 sun hours · 78% humidity · Quiet crowd · UV 8 (very high)

December

2/10

1–7°C (feels 5°C) · 21 rain days (280h) · 227 sun hours · 79% humidity · Quiet crowd · UV 5 (moderate) · sunniest 1 in 10 days reach 6 (high)

Frequently asked questions about visiting Haleakalā

When is the best time to visit Haleakalā?

July is the highest-scoring month (4/10 on the Holiday Climate Index). Typical conditions: 3–10°C (17 rainy days). The top three months by score are July, June, November.

What is the worst time to visit Haleakalā?

March is the lowest-scoring month (1/10). Typical conditions: 1–7°C (27 rainy days).

When are crowds lowest in Haleakalā?

Search-interest seasonality (Google Trends 2021-2025) is lowest in January and peaks in June. Interest tracks both in-trip visitors and lead-time planners, so treat it as a "destination is on people's minds" signal rather than literal arrivals.

What is the UV index in Haleakalā by month?

UV peaks at 11 (very high) in July and is lowest in December at 5 (moderate). Monthly peak values: Jan 6, Feb 7, Mar 8, Apr 9, May 9, Jun 10, Jul 11, Aug 11, Sep 10, Oct 8, Nov 6, Dec 5. March, April, May, June, July, August, September, October reach very high or extreme levels — apply SPF 50+, wear a hat and protective clothing, and limit direct sun between 11:00 and 17:00.

What is the UV index in Haleakalā in July?

July is the peak UV month in Haleakalā, with a daily-peak UV index of 11 (very high). At this level, sunburn can occur in under 20 minutes on unprotected fair skin. Apply SPF 50+, wear protective clothing and a hat, and avoid direct midday sun (11:00–17:00).

How high can UV get in Haleakalā on the sunniest days?

Most days look like the monthly average, but on the sunniest ~1 in 10 days UV climbs higher than the mean suggests. August is the worst case: typical days average UV 11 (very high), but the top 10% of days reach UV 12 (extreme) — and even higher. Months where the sunniest days routinely exceed the typical reading: January, February, March, May, June, July, August, September, December. Plan sun protection for the worst case, not the average.