Boulder monthly weather averages

Contents

Average daytime temperature
Average rainfall
Average daily sunshine
Day / night temperatures
Sea temperature
Wind speed
Relative humidity
Quick weather stats
Location map

Average daytime temperature

The bar chart below shows the average monthly peak daytime temperatures at Boulder

Boulder average temperature chart (Celsius)

Boulder average temperature chart (Fahrenheit)

Average monthly temperatures in Boulder (degrees centigrade and fahrenheit)
	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
°C	32.9	31.6	29	24.5	19.7	16.7	15.8	17.5	21.5	25	28.2	31.5
°F	91.2	88.8	84.1	76.1	67.4	62.1	60.5	63.5	70.6	77.1	82.8	88.7

Please note: these are the average peak daytime temperatures (usually around mid-afternoon) so do not show daytime / night highs and lows. To see the daily range of temperatures have a look at the temperature max / min chart below.

Average rainfall & rainy days

The graph below shows the average rainfall and number of rainy days per month.

Average monthly rainfall in Boulder (mm and inches)
	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
mm	25	26	23	25	33	37	28	22	16	18	19	17
inches	1	1	0.9	1	1.3	1.5	1.1	0.9	0.6	0.7	0.8	0.7
Rainy days	5	7	7	9	12	14	16	15	12	10	6	6

Average annual rainfall in Boulder: 379.767mm (149.5 inches)

Average daily sunshine

The bar chart below shows the average daily sunshine hours in Boulder

Average daily sunshine Boulder
	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Hrs sunshine	11.4	10.2	9.2	7.6	6.9	6.2	6.7	7.9	9.1	9.9	10.4	11.6

Day / night temperatures

The graph below shows the daily range of temperatures for each month.

Boulder average minimum / maximum temperatures (Celsius)

Boulder average minimum / maximum temperatures (Fahrenheit)

Maximum and minimum daily temperatures in Boulder (degrees centigrade and fahrenheit)
	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Min °C	17.6	17.3	15.5	12	7.9	5.6	4.3	4.8	7.2	10.4	13.6	16.1
Max °C	33.3	31.9	29.3	24.8	20	17	16.1	17.8	21.8	25.4	28.6	31.9
Min °F	63.6	63.1	59.9	53.6	46.1	42.1	39.7	40.6	45	50.7	56.5	61
Max °F	77.7	76.3	72.3	65.1	57	52.3	50.4	52.3	58.1	64.2	70	75.2

Sea temperature

The graph below shows the average sea temperature.

Boulder average sea temperature chart (Fahrenheit)

Average sea temperature around Boulder in degrees centigrade and fahrenheit
	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
°C	22.2	22.8	22.8	22.3	21.4	20.2	19.1	18.4	18.3	18.9	19.9	21
°F	71.9	73	73.1	72.2	70.6	68.4	66.4	65.1	65	66.1	67.8	69.9

Wind speed

The graph below shows the average wind speed.

Boulder average winspeed by month (km/h)

Average wind speed in Boulder (mph and kmh)
	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
km/h	15	15	14	13	13	13	14	15	16	16	16	15
mph	9	9	9	8	8	8	9	9	10	10	10	9

A monthly average windspeed of over 16km/h or 10mph suggests a location is fairly windy.

Relative humidity

The graph below shows the average relative humidity.

Average relative humidity in Boulder
Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
32%	37%	40%	46%	54%	60%	59%	51%	41%	35%	33%	31%

Other monthly averages

UV index Best time to go?

Beta

Current (hourly) weather 15 day forecast

Boulder weather stats

Boulder weather statistics
Hottest month:	January	32.9°C 91.2°F
Driest month:	September	16mm 0.6ins
Sunniest month:	December	11.6hrs
Coldest month:	July	15.8°C 60.4°F
Wettest month:	June	37mm 1.5ins
Warmest sea:	March	22.8°C 73°F

Map showing location of Boulder (-30.74614, 121.4742)