Region 18 – Hawaii

Region 18 Forecast : Hawaii | November 2015 – October 2016

SUMMARY: Winter season temperatures will be below normal on the Big Island and Maui; near normal on Molokai, Oahu, Lanai, and Kahoolawe; and above normal on Kauai. The coolest periods will be in late December, early and mid-January, mid-February, and early March. Winter will be much rainier than normal, especially from November into mid-January.

April and May will be much rainier than normal, with temperatures close to normal.

Summer temperatures will be cooler than normal, on average, with slightly below-normal rainfall. The warmest period will be from the latter half of August into early September.

September and October temperatures will be slightly cooler than normal, with near-normal rainfall.

NOTE: Temperature and precipitation vary substantially based upon topography. The detailed forecast focuses on the Honolulu–Waikiki area and provides general trends elsewhere.

KEY: East (E), Central (C), West (W)

NOV. 2015: Temp. 77.5° (avg.); precip. 7.5” (5” above avg.). 1–3 T-storms, cool. 4–8 Showers, warm. 9–12 Sunny, nice C; a few t-storms, cool E + W. 13–18 A few t-storms, turning cool. 19–22 A few showers, warm C; t-storms, turning warm E + W. 23–30 Rainy periods and heavy t-storms, seasonable.

DEC. 2015: Temp. 75° (avg.); precip. 10.3” (7” above avg.). 1–4 T-storms, warm. 5–9 T-storms C, scattered showers E + W; warm. 10–24 Rainy with heavy t-storms C, scattered t-storms E + W; warm, then cool. 25–28 Sunny C + E, showers; cool. 29–31 T-storms, cool.

JAN. 2016: Temp. 73° (avg.); precip. 5.5” (3” above avg.). 1–4 Rainy periods, heavy E; cool. 5–9 Rain and heavy t-storms C + W, sunny E; turning warm. 10–14 Scattered showers C, a few t-storms E + W; cool. 15–18 Scattered showers, turning warm. 19–28 A few t-storms, cool. 29–31 Sunny, warm.

FEB. 2016: Temp. 73.5° (1° below avg. E, 2° above W); precip. 0.5” (1.5” below avg.). 1–6 Widely separated showers, warm. 7–14 Scattered showers, warm C + W; rainy periods, cool E. 15–17 T-storms, cool. 18–29 Scattered showers, warm C + W; daily t-storms, cool E.

MAR. 2016: Temp. 74° (2° below avg. E, 2° above W); precip. 4” (avg. E, 4” above W). 1–8 Daily showers, cool. 9–17 Scattered showers C + E, t-storms W; cool. 18–22 Heavy t-storms, then showers, warm. 23–31 Scattered t-storms; warm C + W, cool E.

APR. 2016: Temp. 75.5° (avg.); precip. 4.7” (10” above avg. E, 1” above C + W). 1–11 Isolated showers C + W, rain and t-storms E; seasonable. 12–18 Showers and t-storms; cool, then warm. 19–30 Brief showers C + W, a few t-storms E; cool E, warm W.

MAY 2016: Temp. 77.5° (1° below avg. E, 2° above W); precip. 0.2” (0.5” below avg.). 1–11 Isolated showers; cool, then warm. 12–31 Brief showers C + W, rainy periods E; cool C + E, warm W.

JUNE 2016: Temp. 79° (0.5° below avg.); precip. 0.4” (avg.). 1–3 Scattered showers, cool. 4–7 Sunny, cool C + E; showers W. 8–16 Isolated showers C + E, scattered t-storms W. 17–30 Isolated showers C, scattered t-storms E + W; cool.

JULY 2016: Temp. 80.5 (0.5° below avg.); precip. 0.3” (0.2” below avg.). 1–5 Daily brief showers, cool C + W; scattered t-storms, warm E. 6–19 Scattered light showers, nice C + W; a few showers, warm E. 20–31 Daily showers, cool.

AUG. 2016: Temp. 81° (0.5° below avg.); precip. 0.6” (avg.). 1–4 Sunny; cool C + W, hot E. 5–15 Daily showers; cool C, warm E + W. 16–31 Scattered showers, warm.

SEPT. 2016: Temp. 81° (0.5° below avg.); precip. 0.8” (avg.). 1–7 A few showers, warm. 8–12 Showers; cool C + W, warm E. 13–18 A few t-storms, cool. 19–30 Daily light showers C + W, rain and t-storms E; seasonable.

OCT. 2016: Temp. 79.5° (0.5° below avg.); precip. 2” (avg.). 1–9 Isolated showers, cool. 10–19 Daily showers, seasonable. 20–23 Showers and t-storms; cool C + W, warm E. 24–31 Isolated showers C + W, several showers E; cool.

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