REGION 18 FORECAST

HAWAII

SUMMARY: Winter season temperatures will be below average in the east and above average in the west, with the coolest periods in early and mid-December, mid-January, early February, and early March. Rainfall will be above normal in the east and below normal in the west, with the stormiest periods in mid-November, from late January into early February, and in early to mid-March. April and May will be cooler than normal in the east and warmer than normal in the west. The months will be slightly drier than normal overall. Summer will be slightly cooler than normal, with the warmest period in late July. Rainfall will be below normal in the east and above normal in the west. September and October will be cooler than normal, with the hottest period in mid-September. Rainfall will be below normal in the east and near normal in the west.

KEY: east (E), central (C), west (W). Note: Temperature and precipitation are substantially based upon topography. The detailed forecast focuses on the Honolulu–Waikiki area and provides general trends elsewhere.

NOV. 2020: Temp. 77.8° (0.5° below avg. E, 1° above W); precip. 2.5" (1" above avg. E, 5" above C, 3" below W). 1–8 A few showers, cool. 9–16 Scattered showers, warm; heavy rain E. 17–20 Heavy rain. 21–30 A few showers, warm; heavy rain E.

DEC. 2020: Temp. 75° (avg.); precip. 2.3" (1" above avg. E, 4" below W). 1–7 Showers, cool. 8–19 Sunny, cool. 20–31 Rainy periods E+W, isolated showers C; warm.

JAN. 2021: Temp. 72.5° (0.5° below avg.); precip. 2.5" (2" below avg. E, 3" above C, 1" below W). 1–7 Rainy periods E+W, sunny C; warm. 8–21 A few showers, cool. 22–28 Rain, then sunny, cool. 29–31 Heavy rain, cool.

FEB. 2021: Temp. 73.5° (avg. E, 1° above W); precip. 3.5" (6" above avg. E, 3" below W). 1–4 Rainy periods, cool. 5–16 Heavy rain E; a few showers, cool C+W. 17–22 Heavy rain E; sunny, cool C+W. 23–28 Rainy periods, seasonable.

MAR. 2021: Temp. 73.5° (0.5° below avg.); precip. 4" (2" above avg.). 1–8 Heavy rain E; scattered showers, cool C+W. 9–17 Showers and t-storms, warm. 18–31 Showers, turning cooler.

ing cooler. APR. 2021: Temp. 76° (0.5° below avg. E, 1.5° above W); precip. 0.2" (0.5" below avg.). 1–8 Scattered showers, seasonable. 9–21 Showers, cool. 22–30 Rainy E, a few showers C+W; seasonable.

MAY 2021: Temp. 77.5° (1° below avg. E, 2° above W); precip. 0.2" (0.5" below avg.). 1–3 Sunny, warm. 4–14 Showers, seasonable. 15–21 Scattered showers, seasonable. 22–31 A few showers, cool.

JUNE 2021: Temp. 79.5° (avg.); precip. 0.2" (0.2" below avg.). 1–12 Scattered showers, cool. 13–20 Rainy periods E+W, isolated showers C; seasonable. 21–30 Daily showers E and W, isolated showers C; warm.

JULY 2021: Temp. 81° (avg.); precip. 0.5" (2" below avg. E, 2" above W). 1–15 Daily showers, warm. 16–23 Showers E and W, isolated showers C; cool. 24–31 A few showers, warm.

AUG. 2021: Temp. 81° (0.5° below avg.); precip. 0.6" (2" below avg. E, 2" above W). 1–10 A few showers, cool. 11–17 Showers E and W, sunny C; seasonable. 18–31 Rainy periods, warm E; a few showers, cool C+W.

SEPT. 2021: Temp. 80° (1.5° below avg.); precip. 0.8 (2" below avg. E, 2" above W). 1–13 A few showers, cool. 14–21 Showers, warm. 22–30 Scattered showers, cool.

OCT. 2021: Temp. 80° (1° above avg. E, 1° below W); precip. 1.5" (1" above avg. E, 2" below W). 1–11 Showers, warm E; isolated showers, cool C+W. 12–21 Rainy periods, some heavy E; scattered showers C+W; warm. 22–31 Showers, warm.