Tehachapi Municipal Airport
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Tehachapi Municipal Airport clear sky chart from 2005-11-06 to 2026-08-30.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.

Observation Type	Minimum conditions for hour to be usable				Out of hours
	Clear of Clouds	Transparency	Seeing	Sky Brightness
Planetary:	50%	(no limit)	Average	(no limit)	Nighttime Hours
Deep Sky:	70%	Average	(no limit)	5.9	Nighttime Hours
CCD Imaging:	70%	Below Average	Poor	(no limit)	Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

By Month

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

		Occurrence of each Forecast	Data Points
Cloud Cover	Day	2 2 1 2 2 3 3 3 5% 6% 72%	151963
	Night	2 2 1 3 3 3 4 3 5% 6% 68%	147837
Transparency	Day	13% 4 4 15% 29% 35%	147045
	Night	14% 6% 5% 16% 29% 30%	143730
Seeing	Day	8% 17% 35% 27% 10% 2	17895
	Night	6% 12% 26% 34% 18% 3	27584

By Month

Percentage Cloud Cover SW (2006-)
Color Meanings: Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	2 3 2 4 4 4 6% 4 10% 8% 54%	4722
	11th to 20th	Day	2 2 1 2 2 3 3 4 6% 9% 67%	5133
	21st to end	Day	3 4 2 5% 4 4 5% 4 6% 8% 54%	6180
February	1st to 10th	Day	4 5% 2 5% 4 4 5% 3 6% 5% 56%	2100
	11th to 20th	Day	4 5% 2 3 5% 5% 6% 5% 8% 9% 50%	2050
	21st to end	Day	3 5% 2 5% 4 5% 5% 4 6% 7% 54%	1730
March	1st to 10th	Day	4 5% 2 5% 4 5% 11% 5% 8% 7% 44%	4618
	11th to 20th	Day	3 5% 2 5% 4 4 7% 4 7% 9% 50%	4824
	21st to end	Day	2 4 2 4 4 4 5% 5% 8% 9% 51%	6101
April	1st to 10th	Day	3 4 1 5% 3 4 5% 4 5% 8% 58%	2520
	11th to 20th	Day	2 3 1 4 3 3 4 4 5% 7% 64%	2489
	21st to end	Day	1 2 1 3 3 3 3 3 5% 9% 66%	2520
May	1st to 10th	Day	1 1 2 2 3 4 3 5% 5% 75%	7283
	11th to 20th	Day	1 1 1 1 1 2 2 4 6% 80%	7596
	21st to end	Day	1 1 2 1 1 2 1 3 5% 82%	8370
June	1st to 10th	Day	1 2 1 2 2 3 3 3 5% 7% 74%	2893
	11th to 20th	Day	1 1 1 1 1 1 2 3 89%	2940
	21st to end	Day	1 1 1 1 1 1 2 3 87%	2940
July	1st to 10th	Day	1 1 1 1 1 2 2 92%	8219
	11th to 20th	Day	1 1 1 2 1 2 2 2 3 5% 81%	8220
	21st to end	Day	1 1 1 1 1 1 1 2 4 88%	8082
August	1st to 10th	Day	1 1 2 1 2 2 2 3 4 83%	5466
	11th to 20th	Day	1 1 1 1 1 1 2 93%	5484
	21st to end	Day	1 1 1 2 2 2 2 3 4 83%	6093
September	1st to 10th	Day	1 1 2 1 2 2 2 3 5% 82%	2400
	11th to 20th	Day	1 1 1 2 2 2 2 3 86%	2275
	21st to end	Day	1 2 1 2 2 2 3 4 83%	2200
October	1st to 10th	Day	1 1 1 2 2 2 2 2 3 4 80%	3600
	11th to 20th	Day	1 1 1 2 1 2 2 4 6% 80%	3294
	21st to end	Day	1 1 1 2 2 4 6% 3 5% 6% 69%	3473
November	1st to 10th	Day	1 3 2 3 3 3 3 3 5% 6% 67%	1854
	11th to 20th	Day	3 3 1 3 2 4 5% 4 4 7% 64%	1890
	21st to end	Day	2 5% 2 3 3 5% 4 5% 7% 6% 58%	1890
December	1st to 10th	Day	2 3 1 3 3 4 5% 4 6% 6% 64%	3040
	11th to 20th	Day	5% 4 2 4 4 4 5% 4 7% 8% 54%	3382
	21st to end	Day	4 6% 2 6% 5% 6% 6% 4 8% 8% 45%	4092
January	1st to 10th	Night	3 3 2 6% 4 4 7% 4 8% 7% 52%	8172
	11th to 20th	Night	1 2 1 3 3 3 3 4 6% 7% 67%	7843
	21st to end	Night	3 5% 2 5% 4 4 5% 5% 7% 7% 52%	8034
February	1st to 10th	Night	3 6% 2 7% 4 5% 5% 4 7% 6% 51%	2520
	11th to 20th	Night	3 5% 2 5% 4 6% 5% 4 7% 7% 51%	2458
	21st to end	Night	4 4 2 5% 5% 5% 5% 4 8% 7% 52%	2076
March	1st to 10th	Night	2 4 2 5% 4 6% 11% 6% 11% 8% 42%	5496
	11th to 20th	Night	2 5% 3 6% 5% 6% 9% 4 7% 6% 48%	5391
	21st to end	Night	2 4 2 5% 4 5% 7% 6% 10% 7% 49%	5116
April	1st to 10th	Night	3 4 2 5% 4 5% 4 4 7% 7% 55%	2100
	11th to 20th	Night	1 3 1 3 3 5% 4 4 7% 6% 63%	2079
	21st to end	Night	1 3 1 3 4 4 4 4 6% 6% 64%	2100
May	1st to 10th	Night	1 1 2 2 3 3 4 2 3 4 75%	5681
	11th to 20th	Night	1 1 1 2 2 1 3 4 84%	5296
	21st to end	Night	1 2 1 2 2 1 2 3 84%	5837
June	1st to 10th	Night	1 2 2 3 3 3 5% 5% 76%	1721
	11th to 20th	Night	1 1 1 2 1 2 3 88%	1680
	21st to end	Night	1 1 1 1 1 2 2 3 89%	1680
July	1st to 10th	Night	1 1 1 1 1 2 92%	4740
	11th to 20th	Night	1 1 1 1 2 2 2 2 3 86%	4740
	21st to end	Night	1 1 1 1 1 1 2 3 89%	6032
August	1st to 10th	Night	1 1 1 1 1 1 2 3 4 86%	4586
	11th to 20th	Night	1 1 1 1 2 93%	4606
	21st to end	Night	1 1 1 1 1 2 1 2 3 87%	5105
September	1st to 10th	Night	1 1 1 1 1 1 2 1 3 87%	2000
	11th to 20th	Night	1 2 1 1 2 2 3 4 84%	2125
	21st to end	Night	2 1 2 3 2 3 3 84%	2200
October	1st to 10th	Night	1 1 1 1 2 2 2 2 4 84%	3600
	11th to 20th	Night	1 1 2 1 2 3 2 4 5% 79%	3859
	21st to end	Night	1 2 1 2 2 2 5% 3 3 4 75%	4332
November	1st to 10th	Night	1 3 1 3 3 4 4 4 6% 7% 64%	2665
	11th to 20th	Night	2 3 1 4 4 4 4 4 6% 7% 61%	2730
	21st to end	Night	3 3 2 4 4 5% 6% 5% 6% 7% 55%	2730
December	1st to 10th	Night	2 3 1 4 3 3 4 4 6% 7% 63%	4370
	11th to 20th	Night	3 3 2 5% 4 4 7% 5% 8% 10% 48%	5031
	21st to end	Night	5% 5% 2 7% 6% 6% 8% 5% 10% 11% 36%	7106

Transparency (when cloud cover <= 30%)
Color Meanings: Too cloudy to forecast Poor Below Average Average Above average Transparent
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	21% 8% 5% 28% 27% 11%	4723
	11th to 20th	Day	14% 6% 6% 13% 26% 36%	5133
	21st to end	Day	25% 6% 5% 14% 28% 21%	6180
February	1st to 10th	Day	25% 7% 5% 18% 24% 21%	2100
	11th to 20th	Day	25% 7% 4 21% 28% 15%	2060
	21st to end	Day	25% 8% 7% 20% 30% 10%	1730
March	1st to 10th	Day	24% 10% 5% 19% 26% 16%	4618
	11th to 20th	Day	22% 8% 8% 29% 22% 10%	4824
	21st to end	Day	20% 11% 12% 28% 23% 7%	6101
April	1st to 10th	Day	21% 7% 7% 25% 28% 12%	2520
	11th to 20th	Day	16% 5% 7% 27% 30% 15%	2492
	21st to end	Day	14% 5% 9% 26% 36% 10%	2520
May	1st to 10th	Day	8% 5% 6% 21% 39% 22%	7283
	11th to 20th	Day	7% 2 3 14% 47% 27%	7599
	21st to end	Day	7% 2 3 15% 50% 23%	8371
June	1st to 10th	Day	11% 4 5% 16% 35% 29%	2893
	11th to 20th	Day	4 2 4 11% 27% 52%	2940
	21st to end	Day	5% 2 2 4 24% 63%	2940
July	1st to 10th	Day	3 1 1 3 11% 81%	8151
	11th to 20th	Day	8% 2 4 9% 20% 57%	8145
	21st to end	Day	5% 1 2 12% 28% 52%	7903
August	1st to 10th	Day	8% 1 2 7% 29% 53%	4010
	11th to 20th	Day	4 1 1 4 20% 69%	4000
	21st to end	Day	5% 1 1 6% 24% 63%	4420
September	1st to 10th	Day	8% 2 2 7% 25% 56%	2400
	11th to 20th	Day	6% 1 2 9% 34% 48%	2275
	21st to end	Day	7% 2 2 10% 36% 43%	2200
October	1st to 10th	Day	8% 3 2 9% 20% 58%	3600
	11th to 20th	Day	8% 2 2 10% 42% 36%	3294
	21st to end	Day	13% 3 3 10% 36% 35%	3473
November	1st to 10th	Day	14% 7% 4 16% 34% 25%	1854
	11th to 20th	Day	18% 5% 5% 18% 28% 27%	1890
	21st to end	Day	22% 7% 6% 14% 25% 24%	1890
December	1st to 10th	Day	20% 5% 5% 15% 30% 26%	3040
	11th to 20th	Day	24% 8% 6% 23% 28% 11%	3381
	21st to end	Day	29% 10% 7% 21% 25% 8%	4092
January	1st to 10th	Night	21% 8% 6% 24% 27% 14%	8172
	11th to 20th	Night	12% 8% 5% 12% 27% 36%	7843
	21st to end	Night	26% 7% 5% 12% 25% 26%	8034
February	1st to 10th	Night	26% 9% 5% 14% 23% 22%	2520
	11th to 20th	Night	26% 8% 4 17% 27% 18%	2459
	21st to end	Night	24% 9% 6% 20% 28% 12%	2076
March	1st to 10th	Night	21% 13% 6% 22% 23% 15%	5496
	11th to 20th	Night	25% 10% 8% 30% 17% 9%	5391
	21st to end	Night	20% 11% 12% 30% 21% 7%	5116
April	1st to 10th	Night	22% 9% 8% 24% 25% 11%	2100
	11th to 20th	Night	16% 6% 8% 25% 32% 14%	2079
	21st to end	Night	14% 6% 6% 30% 35% 8%	2100
May	1st to 10th	Night	9% 6% 5% 23% 44% 13%	5679
	11th to 20th	Night	5% 2 2 22% 50% 19%	5297
	21st to end	Night	6% 2 3 19% 53% 16%	5838
June	1st to 10th	Night	9% 4 7% 19% 37% 23%	1721
	11th to 20th	Night	4 2 4 13% 32% 45%	1680
	21st to end	Night	5% 2 2 5% 29% 58%	1680
July	1st to 10th	Night	3 1 1 3 15% 77%	4700
	11th to 20th	Night	7% 1 3 11% 16% 61%	4692
	21st to end	Night	4 1 2 14% 33% 46%	5899
August	1st to 10th	Night	6% 2 3 7% 34% 48%	3356
	11th to 20th	Night	3 1 1 5% 25% 64%	3356
	21st to end	Night	5% 1 1 7% 26% 60%	3698
September	1st to 10th	Night	6% 2 3 8% 28% 54%	2000
	11th to 20th	Night	4 3 3 10% 37% 43%	2125
	21st to end	Night	6% 3 2 12% 35% 43%	2200
October	1st to 10th	Night	7% 3 2 9% 18% 62%	3600
	11th to 20th	Night	7% 3 2 11% 35% 41%	3859
	21st to end	Night	10% 5% 2 9% 34% 40%	4332
November	1st to 10th	Night	14% 8% 3 16% 31% 28%	2665
	11th to 20th	Night	18% 6% 5% 13% 29% 28%	2730
	21st to end	Night	23% 7% 6% 14% 23% 26%	2730
December	1st to 10th	Night	18% 5% 4 11% 34% 28%	4370
	11th to 20th	Night	23% 9% 9% 20% 23% 16%	5031
	21st to end	Night	31% 11% 8% 18% 24% 8%	7106

Seeing (when cloud cover <= 80%)
Color Meanings: Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	21% 21% 34% 19% 5%	220
	11th to 20th	Day	16% 24% 36% 19% 6%	353
	21st to end	Day	12% 25% 39% 18% 6% 1	536
February	1st to 10th	Day	13% 26% 35% 20% 5% 1	540
	11th to 20th	Day	18% 29% 29% 18% 5% 1	535
	21st to end	Day	13% 28% 37% 17% 4	446
March	1st to 10th	Day	19% 31% 30% 16% 4	540
	11th to 20th	Day	16% 27% 29% 20% 7% 1	540
	21st to end	Day	17% 30% 32% 16% 5% 1	594
April	1st to 10th	Day	14% 25% 35% 16% 9% 1	540
	11th to 20th	Day	14% 26% 35% 19% 6% 1	532
	21st to end	Day	12% 24% 33% 18% 11% 2	540
May	1st to 10th	Day	10% 23% 36% 22% 7% 1	543
	11th to 20th	Day	9% 20% 36% 25% 8% 2	568
	21st to end	Day	8% 20% 33% 28% 10% 1	617
June	1st to 10th	Day	4 13% 39% 30% 12% 3	570
	11th to 20th	Day	2 15% 39% 30% 12% 2	570
	21st to end	Day	3 11% 42% 28% 13% 3	570
July	1st to 10th	Day	6% 40% 36% 13% 4	566
	11th to 20th	Day	1 2 27% 44% 18% 6%	564
	21st to end	Day	1 2 32% 42% 16% 6%	619
August	1st to 10th	Day	1 6% 38% 36% 13% 5%	567
	11th to 20th	Day	1 4 33% 40% 17% 5%	557
	21st to end	Day	1 6% 33% 38% 15% 5%	620
September	1st to 10th	Day	1 6% 37% 35% 17% 4	530
	11th to 20th	Day	3 14% 37% 33% 10% 3	530
	21st to end	Day	4 12% 35% 34% 14% 2	530
October	1st to 10th	Day	5% 15% 34% 32% 14% 1	530
	11th to 20th	Day	6% 16% 35% 33% 9% 2	530
	21st to end	Day	6% 17% 33% 29% 12% 2	534
November	1st to 10th	Day	9% 15% 31% 32% 13% 1	330
	11th to 20th	Day	12% 14% 36% 28% 8% 1	330
	21st to end	Day	7% 23% 36% 24% 8% 1	330
December	1st to 10th	Day	6% 19% 38% 30% 6%	330
	11th to 20th	Day	10% 18% 34% 27% 10% 1	302
	21st to end	Day	21% 28% 26% 19% 5%	242
January	1st to 10th	Night	12% 12% 32% 28% 11% 5%	840
	11th to 20th	Night	5% 15% 33% 33% 11% 3	840
	21st to end	Night	9% 17% 30% 31% 10% 3	924
February	1st to 10th	Night	8% 16% 33% 25% 14% 3	840
	11th to 20th	Night	11% 16% 31% 25% 14% 3	824
	21st to end	Night	9% 18% 30% 31% 10% 2	692
March	1st to 10th	Night	10% 20% 32% 28% 9% 2	840
	11th to 20th	Night	10% 17% 28% 27% 15% 3	840
	21st to end	Night	9% 22% 28% 28% 11% 1	924
April	1st to 10th	Night	8% 23% 32% 24% 11% 2	840
	11th to 20th	Night	7% 20% 31% 29% 11% 2	831
	21st to end	Night	6% 23% 30% 26% 13% 3	840
May	1st to 10th	Night	5% 19% 36% 28% 11% 1	756
	11th to 20th	Night	5% 19% 30% 34% 11% 1	621
	21st to end	Night	5% 19% 35% 30% 11%	683
June	1st to 10th	Night	2 11% 36% 41% 10% 1	461
	11th to 20th	Night	10% 32% 42% 14% 1	420
	21st to end	Night	1 6% 31% 42% 19%	420
July	1st to 10th	Night	1 1 20% 49% 28% 1	410
	11th to 20th	Night	1 9% 55% 33% 1	408
	21st to end	Night	2 1 15% 43% 34% 4	762
August	1st to 10th	Night	1 2 21% 45% 28% 3	836
	11th to 20th	Night	1 1 19% 43% 31% 6%	832
	21st to end	Night	2 1 11% 44% 34% 7%	916
September	1st to 10th	Night	1 3 11% 42% 36% 6%	800
	11th to 20th	Night	1 4 19% 41% 29% 5%	800
	21st to end	Night	1 7% 19% 40% 28% 7%	800
October	1st to 10th	Night	3 8% 21% 44% 22% 2	800
	11th to 20th	Night	4 8% 22% 37% 22% 6%	800
	21st to end	Night	3 11% 23% 34% 20% 9%	880
November	1st to 10th	Night	5% 11% 24% 34% 20% 6%	820
	11th to 20th	Night	6% 8% 27% 36% 18% 5%	840
	21st to end	Night	6% 13% 28% 33% 17% 3	840
December	1st to 10th	Night	7% 12% 31% 32% 16% 2	840
	11th to 20th	Night	10% 13% 31% 33% 11% 2	840
	21st to end	Night	13% 15% 29% 29% 11% 2	924

Page generated at 2026-08-27 01:07:10. Version ac07

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