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Rain

Pittsburgh...
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Rain

I am curious to know about the rain pattern on the east side of Hawaii.

Does it rain EVERY day?

When it does rain is it usually AM, PM, overnight mostly?

How long does it last?

I am thinking I could arrange my trip to the east side around the local forecast.

Portland, OR
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1. Re: Rain

My experience with rain on the east side is it is unpredictable. I gave up long ago trying to figure out when it would rain, except it usually rains during Merry Monarch and during the County Fair.

Rain on the Big Island is much more a function of location then season. Time of day does matter, to some extent but not to the point where one can plan around afternoon showers and sunny mornings. Think of it this way: warm moist air is blown across the vast Pacific Ocean, absorbing moisture. The air gets heavy with the moisture and sinks lower, continuing to pick up moisture, until eventually the saturation in the air is too great and water drop lets form. This is a simplified explanation of rain. Think of the Big Island as a very, very large rock. As the warm moist air gets pushed against the rock, it is forced to rise. As it does, it cools and precipitation forms. The higher the moist air goes, the more the cloud releases, to the point where the air is light enough to cross over the top of the rock, and leaving the now dry air mass to move to areas of lower pressure, i.e. mauka. This creates the rain shadow effect on the Big Island and why when driving through Waimea there is a wet side and a “dry” side and there is a clear defined line where that happens. Generally speaking: the higher up on the windward side of any island, the wetter, and the dryer on the lee side. This is why Kona is drier than Hilo. The Hamakua coast gets a lot of precipitation, and it makes sense why. The Kau area is called a desert for this reason.

Knowing where (in terms of elevation) on the island you will be helps determine the potential for precipitation, but the islands are in the tropics and rain can neither be forecasted nor predicted with a high degree of accuracy. Instead of attempting to plan an entire day trip around the forecast, be flexible, if it is dumping down rain in Hilo then maybe stay on the west side and try tomorrow. Remember, just because it is raining in one spot on the island, doesn’t mean it is raining everywhere. Listen to the radio for weather updates; they give both sides of the island now.

My last bit of advice is from a Hilo boy – rain never stops me from doing something I really wanted to do. But that’s because I grew up with the rain.

Good luck and happy travels!

Kona, Hawaii
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2. Re: Rain

Usually the rain is warm, not like Pittsburgh rain.. Hilo/Volcano Village areas are rainy so bring a slicker.

Island of Hawaii...
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for Hilo, Island of Hawaii
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3. Re: Rain

Wow, what a great explanation from echolynch!

>>>except it usually rains during Merry Monarch and during the County Fair.

ROFL

echo, you forgot Fourth of July, Halloween, and New Year's Eve.

beachtraveler, you didn't say what month you are coming. It can rain at any season, like echo said, but in winter there are more of what I'd call real storms, when it sets in pouring all day for days on end.

I hardly saw the sun from January to April this year, but once it turned May it's been quite sunny. I don't expect it to last though. I remember in 2006 it rained July thru September.

You can use the NOAA forecast to watch out for real storms. If it says rain 80% or better, or Heavy Rain, then those will be soggy days for sure. If it says 30% scattered showers, that's probably going to be a nice enough day with intermittent showers.

The forecast is reliable for a specific day MAYBE two days out, and no more than seven for the overall pattern.

Pittsburgh...
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4. Re: Rain

I will be there at the end of May

Kona, Hawaii
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5. Re: Rain

It will rain end of May ;o)

Island of Hawaii...
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for Hilo, Island of Hawaii
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6. Re: Rain

Most likely it will ... ;-)

but unlikely you will get a stormy period, more likely intermittent showers or even nice weather. This week is glorious Hilo weather. Blue skies, white clouds, blue ocean, but hotter than normal.

You didn't say what you mean by arrange your trip, whether you mean overnight days (forecast not much help) or day trips (forecast is useful if you build in flexibility).

Rain shouldn't stop you from coming, but I think it's more beautiful if you get to see it lit up by sunshine, at least part of the day.

In the most common pattern, you will see early morning rain and late afternoon/evening. But, as echo said, the weather doesn't adhere to that pattern. A squall can blow in at noon, or any time of day, and very suddenly too. Bring an umbrella.

Island of Hawaii...
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7. Re: Rain

Rain pattern?! Even those who live there can't figure it out! :):):) However, it's a warm rain and rarely last long. Bring/buy an umbrella and you will be fine.

Pittsburgh...
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8. Re: Rain

Actually why I was asking was that we are staying on the west side but are planning a day trip to the east side and of course would like a sunny day:)

Island of Hawaii...
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for Hilo, Island of Hawaii
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9. Re: Rain

This is what I use for that:

forecast.weather.gov/MapClick.php…

That's Hilo

For the Botanical Gardens use 96781 (Papaikou) or click on the map for a point forecast.

Best of luck!

Today's graphics are as good as it gets. You will almost never see a full sun graphic and only if the winds have shifted, so that usually means nasty vog. 20-30% possible showers is an excellent day.

Pittsburgh, PA
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10. Re: Rain

We just got back from the Waikoloa Beach area and I can tell you that it poured down rain during the early morning of Mother's day and on Monday it rain in the Capt. Cook area but was dry and sunny in Hilo and VNP.

The question I have of the locals is that it seemed to me to be very humid last week in Waikola Beach and Kona. It reminded me of Pittsburgh summers, Hazy, Hot and Humid. Is that normal?