Riverside weather by month
What a typical year looks like in Riverside, Idaho: average highs and lows, rain and snow, and the warmest and coldest days on record. Normals are the 1991–2020 averages at BLACKFOOT FIRE DEPARTMENT, 7 km from Riverside; records cover 1895–2026.
The year at a glance
- Precipitation a year
- 12.1 in306 mm
- Snow a year
- 15 in37 cm
- Last spring freeze
- May 10
- First fall freeze
- Oct 3
- Heating degree days
- 6,991
- Cooling degree days
- 519
Freeze dates are medians (half of years earlier, half later). Degree days use a 65°F base; HVAC design temperatures here are −4°−20° (heating, 99%) and 96°36° (cooling, 1%).
Month by month
Riverside in January
Highs average 31°0° and lows 17°−8°, with 0.99 in25 mm of precipitation and 6 in15 cm of snow in a typical January.
- Record high
- 60°16° (1981)
- Record low
- −40° (1937)
- Heating degree days
- 1271
- Cooling degree days
- 0
Riverside in February
Highs average 37°3° and lows 21°−6°, with 0.73 in19 mm of precipitation and 2.2 in5.6 cm of snow in a typical February.
- Record high
- 81°27° (1896)
- Record low
- −39° (1933)
- Heating degree days
- 1015
- Cooling degree days
- 0
Riverside in March
Highs average 49°9° and lows 29°−2°, with 1.1 in28 mm of precipitation and 0.3 in0.8 cm of snow in a typical March.
- Record high
- 79°26° (1900)
- Record low
- −19°−28° (1922)
- Heating degree days
- 808
- Cooling degree days
- 0
Riverside in April
Highs average 57°14° and lows 35°2°, with 1.4 in36 mm of precipitation and 0.7 in1.8 cm of snow in a typical April.
- Record high
- 88°31° (1946)
- Record low
- 6°−14° (1936)
- Heating degree days
- 569
- Cooling degree days
- 0
Riverside in May
Highs average 68°20° and lows 43°6°, with 1.8 in44 mm of precipitation in a typical May.
- Record high
- 96°36° (2003)
- Record low
- 17°−8° (1972)
- Heating degree days
- 315
- Cooling degree days
- 12
Riverside in June
Highs average 77°25° and lows 50°10°, with 1 in26 mm of precipitation in a typical June.
- Record high
- 108°42° (1900)
- Record low
- 24°−4° (1899)
- Heating degree days
- 120
- Cooling degree days
- 68
Riverside in July
Highs average 87°31° and lows 56°13°, with 0.5 in13 mm of precipitation in a typical July.
- Record high
- 104°40° (2023)
- Record low
- 30°−1° (1912)
- Heating degree days
- 18
- Cooling degree days
- 218
Riverside in August
Highs average 86°30° and lows 54°12°, with 0.6 in15 mm of precipitation in a typical August.
- Record high
- 104°40° (1958)
- Record low
- 23°−5° (1910)
- Heating degree days
- 23
- Cooling degree days
- 179
Riverside in September
Highs average 75°24° and lows 46°8°, with 0.97 in25 mm of precipitation in a typical September.
- Record high
- 99°37° (2022)
- Record low
- 12°−11° (1926)
- Heating degree days
- 174
- Cooling degree days
- 41
Riverside in OctoberThis month
Highs average 61°16° and lows 35°2°, with 1.1 in28 mm of precipitation and 0.8 in2 cm of snow in a typical October.
- Record high
- 88°31° (1910)
- Record low
- −1°−18° (2019)
- Heating degree days
- 536
- Cooling degree days
- 1
Riverside in November
Highs average 45°7° and lows 26°−4°, with 0.75 in19 mm of precipitation and 1.4 in3.6 cm of snow in a typical November.
- Record high
- 74°23° (1999)
- Record low
- −24°−31° (1896)
- Heating degree days
- 896
- Cooling degree days
- 0
Riverside in December
Highs average 32°0° and lows 18°−8°, with 1.1 in28 mm of precipitation and 3 in8 cm of snow in a typical December.
- Record high
- 61°16° (1995)
- Record low
- −30°−34° (1924)
- Heating degree days
- 1246
- Cooling degree days
- 0