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Weather on December 17

Rialto, CA

55 Years of Data

Avg High
65°F
Avg Low
45°F
Warmest
1999
73°F avg
Coldest
2008
39°F avg

About This Date

December 17th in Rialto, CA typically brings mild winter weather, with average highs around 65°F and lows near 45°F. Over 47 years of records, the warmest December 17th was in 1999 (73°F average), while the coldest was 2008 (39°F) — a 34°F range across recorded history. Rain or other precipitation has occurred on about 6% of December 17th dates historically, with the wettest December 17th recording 1.57" of rain.

Planning for December 17th in Rialto, CA? Great weather for outdoor activities.

Cooling Trend
0.6°F per decade on this date
YearHighLowAvgPrecipSnow
202577°51°64°
201655°36°45°
201564°41°53°
201453°45°49°
201378°64°71°
201253°47°50°
201158°45°51°
201051°45°48°
200968°53°61°
2008coldest44°33°39°
200756°41°48°
200648°38°43°
200552°44°48°
200470°55°62°
200365°48°56°
200253°39°46°
200166°41°54°
200078°56°67°
1999warmest86°59°73°
199882°52°67°
199772°46°59°
199667°63°65°
199564°48°56°
199470°53°61°
199362°42°52°
199252°38°45°
199163°52°57°
199059°38°48°
198966°35°51°
198856°42°49°0.89"
198749°40°44°1.57"
198669°42°56°
198575°43°59°
198460°27°43°
198363°53°58°
198272°35°53°
198178°47°62°
198082°51°67°
197984°41°63°
197857°45°51°
197767°43°55°0.15"
197677°38°57°
197567°55°61°
197476°42°59°
197376°41°58°
197270°42°56°
197167°33°50°
47 years of data from FONTANA 5 N

Rialto, CA Temperature Range by Month

Average monthly highs and lows. The shaded band shows the typical daily temperature range.

30°50°70°90°JFMAMJJASOND
Avg high Avg low

Rialto, CA Monthly Precipitation

Average rainfall and snowfall per month, in inches.

0"6.7"13.3"JFMAMJJASOND0.1"0"
Rain (in) Snow (in)

Rialto, CA Daily Temperature Calendar

Average daily high temperature for every day of the year. Each cell is the climatological mean for that calendar day across 55 years of NOAA data.

151015202531JanFebMarAprMayJunJulAugSepOctNovDec
Cooler
Hotter
20°40°60°80°100°

Best Time to Visit Rialto, CA

Rialto, CA has no months that meet our "pleasant" threshold — every season has tradeoffs.

Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Pleasant (65-82°F, ≤2.5" rain) Mild Less ideal

Browse Weather History

Weather data provided by NOAA Climate Data Online. Not for critical planning.

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