As of 04:54 PDT

Costa Mesa, CA weather in September

69°

Costa Mesa, Sunday, 9 August, 04:54

Mostly clear. Feels like 70°. High 97°, low 69°.

Pressure29.85 inHg

Wind3.2 mph SW

Humidity92%

Visibility6.2 mi

Dew point67°

See detailed hourly forecast

In September, Costa Mesa, CA averages a high of 78.1° and a low of 63.7°. About 0.3 inches of precipitation fall over the month (1 wet days). The record high is 104° (1988) and the record low 53.1° (2024). Normals are computed over the last 60 years.

Day	High	Low	Chance of precip.	Record high	Record low
1	80.1°	65.1°	2%	94.6° (1998)	57.4° (1973)
2	80.2°	65.7°	2%	92.5° (1982)	59.7° (1966)
3	80.2°	65.5°	5%	95.5° (1988)	59.4° (1961)
4	81°	65.5°	2%	104° (1988)	57.9° (1999)
5	80.6°	65.5°	3%	95.9° (1984)	57.2° (1973)
6	80.6°	65.5°	2%	93.9° (2020)	58.1° (1964)
7	80.1°	65.3°	0%	88° (2013)	57.6° (1980)
8	79.7°	65.1°	0%	94.5° (1984)	57.6° (1980)
9	79°	65.1°	3%	95.4° (2022)	58.5° (1962)
10	77.9°	64.4°	5%	92.1° (1983)	57.4° (1975)
11	77.5°	63.7°	5%	93.4° (1983)	57° (1975)
12	77.2°	63.7°	0%	95.4° (1971)	57.4° (1972)
13	76.5°	63.5°	2%	96.1° (1971)	56.8° (2021)
14	77°	63.1°	2%	92.5° (2014)	56.8° (1970)
15	77°	63.1°	5%	93.4° (1979)	57° (1964)
16	76.8°	63.3°	5%	93.6° (2014)	57.6° (1999)
17	76.6°	63.3°	2%	89.6° (1979)	57.4° (2005)
18	76.6°	63°	5%	92.1° (1984)	55.8° (1993)
19	76.1°	62.8°	2%	92.7° (1984)	53.2° (1978)
20	75.7°	62.6°	10%	89.6° (2015)	56.5° (1989)
21	76.8°	62.4°	2%	87.1° (1972)	55.4° (1965)
22	77.9°	62.6°	3%	88.7° (1992)	55.2° (1964)
23	78.3°	62.6°	3%	97° (1975)	56.3° (1986)
24	78.3°	63.1°	5%	97° (1978)	57.6° (1973)
25	77.9°	63°	7%	94.6° (1963)	57.2° (1970)
26	77.2°	63.1°	5%	102.6° (1963)	55.6° (2024)
27	77.2°	62.8°	2%	97° (1970)	55° (2013)
28	77.4°	62.6°	3%	96.4° (1963)	54.7° (2013)
29	77.2°	62.8°	8%	94.5° (1999)	53.1° (2024)
30	77.7°	62.6°	3%	95.5° (2020)	56.3° (1975)