Carmel
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Carmel clear sky chart from 2005-11-06 to 2026-06-01.

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	13% 9% 4 8% 5% 4 4 4 6% 7% 35%	131648
	Night	14% 10% 4 8% 5% 4 4 3 5% 7% 36%	131690
Transparency	Day	46% 6% 11% 22% 13% 2	135244
	Night	47% 5% 10% 22% 14% 2	136168
Seeing	Day	17% 12% 27% 23% 14% 6%	17673
	Night	18% 10% 29% 28% 13% 1	27551

By Month

Percentage Cloud Cover SE (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	14% 15% 8% 13% 6% 4 4 3 5% 6% 24%	4691
	11th to 20th	Day	9% 14% 7% 14% 7% 7% 7% 5% 4 4 20%	4710
	21st to end	Day	17% 16% 7% 14% 5% 4 4 4 4 4 21%	5367
February	1st to 10th	Day	18% 13% 6% 9% 7% 5% 4 3 4 5% 26%	2091
	11th to 20th	Day	15% 12% 4 12% 6% 5% 4 3 4 6% 29%	2048
	21st to end	Day	15% 14% 5% 10% 4 3 3 3 5% 5% 32%	1730
March	1st to 10th	Day	20% 16% 5% 8% 4 3 3 3 3 4 32%	4580
	11th to 20th	Day	11% 10% 3 7% 4 4 4 3 5% 8% 42%	4920
	21st to end	Day	16% 12% 4 9% 5% 4 5% 4 5% 6% 30%	5831
April	1st to 10th	Day	16% 10% 3 9% 5% 4 4 3 5% 7% 34%	2520
	11th to 20th	Day	16% 9% 3 7% 5% 4 4 3 6% 7% 35%	2494
	21st to end	Day	19% 7% 3 7% 5% 4 4 3 4 7% 36%	2704
May	1st to 10th	Day	19% 10% 4 8% 5% 5% 5% 4 6% 7% 28%	5992
	11th to 20th	Day	18% 7% 3 7% 5% 5% 4 3 5% 7% 36%	5991
	21st to end	Day	12% 7% 3 7% 5% 5% 5% 5% 7% 9% 34%	6750
June	1st to 10th	Day	11% 6% 3 6% 5% 5% 5% 3 6% 8% 41%	2801
	11th to 20th	Day	9% 6% 2 6% 4 5% 5% 5% 7% 9% 43%	2800
	21st to end	Day	9% 6% 2 6% 6% 5% 5% 4 6% 10% 41%	2800
July	1st to 10th	Day	10% 6% 2 6% 4 5% 5% 5% 7% 11% 39%	6360
	11th to 20th	Day	8% 6% 3 7% 5% 5% 5% 5% 8% 11% 37%	6360
	21st to end	Day	10% 7% 2 8% 5% 6% 6% 5% 7% 8% 36%	6744
August	1st to 10th	Day	8% 5% 2 5% 4 4 5% 4 7% 10% 47%	4234
	11th to 20th	Day	8% 5% 2 6% 4 5% 5% 4 7% 11% 42%	4011
	21st to end	Day	6% 4 2 6% 4 4 4 3 6% 10% 50%	4312
September	1st to 10th	Day	11% 6% 2 7% 4 4 4 3 7% 7% 46%	2366
	11th to 20th	Day	9% 5% 2 5% 3 4 4 4 6% 8% 49%	2200
	21st to end	Day	14% 5% 2 5% 4 4 3 3 5% 6% 47%	2200
October	1st to 10th	Day	11% 6% 2 6% 4 4 4 3 5% 7% 48%	2200
	11th to 20th	Day	13% 7% 2 7% 4 3 4 4 5% 7% 44%	2035
	21st to end	Day	17% 10% 4 8% 3 4 4 4 5% 6% 35%	1980
November	1st to 10th	Day	8% 8% 2 6% 4 4 3 3 5% 6% 50%	1852
	11th to 20th	Day	16% 12% 3 9% 4 3 3 3 5% 6% 35%	1890
	21st to end	Day	18% 11% 4 8% 5% 3 4 2 5% 5% 33%	1890
December	1st to 10th	Day	13% 12% 4 8% 4 3 3 3 3 5% 40%	3020
	11th to 20th	Day	16% 16% 5% 12% 5% 5% 4 3 5% 5% 24%	3104
	21st to end	Day	25% 19% 7% 10% 5% 5% 4 3 4 5% 13%	4070
January	1st to 10th	Night	15% 14% 7% 13% 6% 4 4 3 5% 5% 24%	8232
	11th to 20th	Night	10% 17% 7% 15% 7% 6% 5% 4 4 4 21%	8280
	21st to end	Night	17% 12% 5% 8% 6% 5% 4 4 5% 5% 28%	8820
February	1st to 10th	Night	17% 14% 4 10% 5% 5% 4 3 5% 6% 27%	2525
	11th to 20th	Night	14% 13% 5% 10% 5% 4 4 3 4 6% 32%	2458
	21st to end	Night	18% 11% 4 11% 4 3 4 3 5% 6% 31%	2076
March	1st to 10th	Night	19% 13% 4 7% 3 3 3 2 4 5% 38%	5493
	11th to 20th	Night	12% 7% 2 6% 5% 4 4 3 5% 7% 44%	5260
	21st to end	Night	17% 10% 4 8% 5% 4 4 3 6% 6% 34%	5383
April	1st to 10th	Night	14% 10% 3 6% 5% 4 4 4 5% 8% 37%	2100
	11th to 20th	Night	16% 8% 2 6% 4 4 4 3 5% 7% 40%	2075
	21st to end	Night	16% 8% 3 7% 4 4 4 4 6% 7% 36%	1913
May	1st to 10th	Night	19% 10% 4 9% 6% 5% 4 4 5% 7% 28%	4123
	11th to 20th	Night	16% 7% 3 7% 4 4 4 3 6% 9% 38%	4122
	21st to end	Night	13% 8% 3 7% 4 4 5% 4 6% 9% 38%	4349
June	1st to 10th	Night	9% 6% 2 7% 4 4 3 4 5% 8% 48%	1600
	11th to 20th	Night	10% 6% 2 6% 3 4 5% 3 5% 8% 46%	1600
	21st to end	Night	6% 4 3 7% 4 4 5% 5% 7% 11% 45%	1600
July	1st to 10th	Night	8% 4 2 6% 4 4 5% 4 6% 10% 46%	3618
	11th to 20th	Night	8% 5% 2 6% 4 4 5% 4 7% 9% 47%	3617
	21st to end	Night	9% 7% 3 8% 5% 5% 5% 4 6% 9% 40%	4120
August	1st to 10th	Night	10% 5% 1 6% 4 4 4 3 6% 9% 50%	2915
	11th to 20th	Night	7% 6% 2 7% 5% 4 5% 4 6% 9% 45%	3034
	21st to end	Night	5% 4 2 6% 4 4 4 4 6% 7% 55%	3586
September	1st to 10th	Night	12% 6% 2 5% 5% 3 4 3 5% 6% 50%	2012
	11th to 20th	Night	7% 4 2 4 3 4 4 3 5% 7% 56%	2200
	21st to end	Night	12% 6% 2 6% 3 4 3 3 5% 7% 49%	2200
October	1st to 10th	Night	8% 4 2 5% 4 4 4 3 5% 7% 54%	2200
	11th to 20th	Night	17% 6% 2 4 3 3 3 3 4 7% 46%	2358
	21st to end	Night	17% 8% 3 6% 4 4 4 3 5% 6% 40%	2860
November	1st to 10th	Night	12% 7% 2 6% 3 3 3 3 5% 6% 49%	2666
	11th to 20th	Night	14% 10% 3 7% 4 3 4 3 5% 7% 39%	2730
	21st to end	Night	18% 13% 4 8% 5% 4 4 3 4 6% 31%	2730
December	1st to 10th	Night	14% 10% 4 8% 6% 3 4 3 4 6% 38%	4380
	11th to 20th	Night	17% 15% 6% 10% 5% 4 4 3 4 5% 27%	5305
	21st to end	Night	26% 19% 5% 10% 5% 4 4 3 4 4 15%	7150

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	62% 3 11% 18% 5% 1	4692
	11th to 20th	Day	67% 4 8% 10% 9% 2	4710
	21st to end	Day	68% 3 8% 15% 5% 2	5367
February	1st to 10th	Day	61% 5% 9% 16% 9% 1	2091
	11th to 20th	Day	58% 5% 8% 20% 9% 1	2058
	21st to end	Day	54% 5% 10% 21% 8% 2	1730
March	1st to 10th	Day	58% 4 5% 20% 11% 2	4580
	11th to 20th	Day	41% 5% 8% 33% 12% 1	4920
	21st to end	Day	54% 5% 13% 18% 9% 1	5833
April	1st to 10th	Day	51% 6% 11% 20% 13% 1	2520
	11th to 20th	Day	47% 6% 11% 23% 10% 3	2494
	21st to end	Day	49% 5% 10% 24% 11% 2	2704
May	1st to 10th	Day	53% 7% 11% 19% 10%	6027
	11th to 20th	Day	48% 7% 11% 24% 11% 1	5995
	21st to end	Day	43% 8% 12% 23% 14% 1	6764
June	1st to 10th	Day	40% 7% 12% 23% 16% 3	2801
	11th to 20th	Day	35% 7% 12% 23% 20% 2	2800
	21st to end	Day	38% 7% 15% 20% 17% 4	2800
July	1st to 10th	Day	38% 6% 11% 26% 18% 2	6291
	11th to 20th	Day	37% 9% 16% 24% 13% 1	6285
	21st to end	Day	43% 8% 13% 21% 13% 2	6551
August	1st to 10th	Day	31% 8% 16% 29% 15% 1	4221
	11th to 20th	Day	34% 8% 13% 31% 14%	4050
	21st to end	Day	29% 7% 12% 31% 17% 4	4311
September	1st to 10th	Day	36% 6% 10% 26% 18% 4	2366
	11th to 20th	Day	31% 7% 10% 27% 22% 3	2200
	21st to end	Day	36% 5% 10% 24% 24% 1	2200
October	1st to 10th	Day	24% 4 9% 32% 30% 2	3590
	11th to 20th	Day	33% 5% 9% 26% 25% 1	3290
	21st to end	Day	41% 4 9% 24% 21% 1	3180
November	1st to 10th	Day	36% 4 13% 27% 18% 3	1852
	11th to 20th	Day	50% 4 9% 20% 13% 3	1890
	21st to end	Day	54% 3 10% 22% 9% 1	1890
December	1st to 10th	Day	48% 3 10% 27% 12%	3020
	11th to 20th	Day	62% 5% 10% 18% 5%	3101
	21st to end	Day	73% 4 9% 10% 4	4070
January	1st to 10th	Night	62% 4 10% 17% 7%	8233
	11th to 20th	Night	66% 4 7% 11% 10% 2	8280
	21st to end	Night	57% 4 11% 19% 8% 1	8820
February	1st to 10th	Night	58% 4 11% 17% 8% 1	2525
	11th to 20th	Night	53% 4 10% 19% 12% 1	2459
	21st to end	Night	54% 4 12% 18% 10% 2	2076
March	1st to 10th	Night	50% 4 6% 25% 12% 3	5493
	11th to 20th	Night	39% 6% 10% 27% 17% 2	5260
	21st to end	Night	50% 5% 9% 27% 8% 1	5383
April	1st to 10th	Night	44% 6% 13% 22% 14% 2	2100
	11th to 20th	Night	44% 5% 10% 21% 16% 4	2075
	21st to end	Night	45% 7% 9% 23% 12% 4	1913
May	1st to 10th	Night	55% 7% 8% 17% 11% 2	4150
	11th to 20th	Night	43% 6% 12% 25% 13% 1	4123
	21st to end	Night	42% 7% 13% 23% 13% 2	4357
June	1st to 10th	Night	34% 7% 9% 26% 21% 4	1600
	11th to 20th	Night	36% 7% 10% 23% 21% 4	1600
	21st to end	Night	31% 8% 15% 24% 18% 4	1600
July	1st to 10th	Night	33% 6% 11% 28% 18% 4	3580
	11th to 20th	Night	31% 8% 14% 29% 16% 1	3572
	21st to end	Night	39% 7% 14% 24% 13% 3	4001
August	1st to 10th	Night	32% 7% 14% 32% 15% 1	2904
	11th to 20th	Night	34% 7% 13% 28% 17% 1	3061
	21st to end	Night	27% 5% 12% 30% 22% 3	3586
September	1st to 10th	Night	34% 6% 10% 23% 21% 6%	2012
	11th to 20th	Night	28% 5% 9% 27% 28% 4	2200
	21st to end	Night	35% 6% 9% 23% 24% 3	2200
October	1st to 10th	Night	20% 4 7% 27% 39% 2	3590
	11th to 20th	Night	29% 3 9% 25% 33% 2	3842
	21st to end	Night	34% 4 8% 26% 25% 3	4610
November	1st to 10th	Night	37% 4 9% 26% 22% 3	2666
	11th to 20th	Night	44% 3 10% 23% 17% 3	2730
	21st to end	Night	56% 4 8% 22% 10%	2730
December	1st to 10th	Night	48% 3 11% 26% 11%	4380
	11th to 20th	Night	60% 3 10% 16% 9% 1	5307
	21st to end	Night	73% 4 9% 10% 4	7150

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	24% 21% 32% 21% 3	330
	11th to 20th	Day	22% 24% 36% 12% 5%	330
	21st to end	Day	28% 21% 31% 16% 4	363
February	1st to 10th	Day	26% 17% 35% 18% 5%	330
	11th to 20th	Day	23% 23% 34% 15% 5%	330
	21st to end	Day	25% 18% 41% 15% 1	273
March	1st to 10th	Day	23% 23% 36% 15% 2	330
	11th to 20th	Day	27% 19% 32% 15% 6%	461
	21st to end	Day	27% 19% 32% 16% 5% 1	594
April	1st to 10th	Day	18% 21% 36% 17% 7% 1	540
	11th to 20th	Day	21% 19% 29% 19% 10% 2	532
	21st to end	Day	23% 16% 33% 19% 7% 2	540
May	1st to 10th	Day	22% 14% 35% 18% 10% 2	543
	11th to 20th	Day	22% 10% 29% 22% 11% 6%	567
	21st to end	Day	14% 9% 28% 24% 18% 8%	687
June	1st to 10th	Day	12% 7% 31% 29% 16% 5%	731
	11th to 20th	Day	13% 6% 25% 34% 16% 6%	730
	21st to end	Day	12% 7% 28% 27% 19% 7%	730
July	1st to 10th	Day	12% 3 19% 27% 23% 15%	721
	11th to 20th	Day	8% 5% 21% 34% 22% 10%	718
	21st to end	Day	10% 3 18% 32% 27% 10%	714
August	1st to 10th	Day	10% 3 16% 25% 30% 15%	526
	11th to 20th	Day	10% 4 20% 29% 25% 13%	519
	21st to end	Day	6% 3 16% 32% 30% 14%	583
September	1st to 10th	Day	11% 6% 16% 29% 27% 11%	530
	11th to 20th	Day	9% 3 13% 28% 30% 17%	530
	21st to end	Day	17% 8% 22% 20% 22% 10%	530
October	1st to 10th	Day	10% 8% 21% 34% 18% 8%	530
	11th to 20th	Day	13% 17% 31% 24% 13% 2	455
	21st to end	Day	26% 17% 35% 20% 2	363
November	1st to 10th	Day	13% 20% 33% 21% 13% 2	330
	11th to 20th	Day	24% 19% 31% 17% 7% 2	330
	21st to end	Day	26% 14% 37% 20% 3	330
December	1st to 10th	Day	19% 24% 38% 14% 4 1	330
	11th to 20th	Day	21% 22% 35% 16% 5%	330
	21st to end	Day	29% 20% 32% 15% 4	363
January	1st to 10th	Night	24% 16% 33% 23% 4	1050
	11th to 20th	Night	25% 16% 37% 18% 3	1050
	21st to end	Night	23% 17% 34% 23% 3	1073
February	1st to 10th	Night	25% 13% 34% 26% 2	840
	11th to 20th	Night	21% 16% 37% 23% 3	823
	21st to end	Night	24% 13% 39% 21% 2	692
March	1st to 10th	Night	22% 16% 33% 23% 5%	840
	11th to 20th	Night	19% 16% 37% 22% 6% 1	840
	21st to end	Night	24% 12% 32% 27% 5%	835
April	1st to 10th	Night	19% 14% 36% 24% 7%	630
	11th to 20th	Night	20% 12% 31% 28% 9%	623
	21st to end	Night	20% 10% 39% 24% 7% 1	630
May	1st to 10th	Night	20% 11% 36% 24% 9%	630
	11th to 20th	Night	19% 6% 28% 29% 16% 1	621
	21st to end	Night	10% 5% 27% 36% 20% 2	683
June	1st to 10th	Night	11% 4 27% 43% 15% 1	600
	11th to 20th	Night	13% 4 20% 43% 19% 1	600
	21st to end	Night	7% 4 25% 38% 25% 1	600
July	1st to 10th	Night	10% 2 14% 37% 32% 6%	585
	11th to 20th	Night	7% 3 19% 38% 29% 4	582
	21st to end	Night	8% 2 17% 40% 30% 3	657
August	1st to 10th	Night	8% 1 16% 38% 34% 4	597
	11th to 20th	Night	7% 2 13% 41% 31% 5%	594
	21st to end	Night	7% 1 16% 34% 37% 5%	660
September	1st to 10th	Night	13% 4 14% 34% 31% 4	612
	11th to 20th	Night	8% 3 16% 34% 35% 4	800
	21st to end	Night	15% 5% 21% 32% 25% 2	800
October	1st to 10th	Night	11% 6% 22% 36% 21% 5%	800
	11th to 20th	Night	20% 10% 29% 27% 13% 1	800
	21st to end	Night	21% 12% 36% 25% 6% 1	880
November	1st to 10th	Night	17% 9% 34% 27% 12% 1	820
	11th to 20th	Night	17% 16% 33% 26% 7% 1	840
	21st to end	Night	27% 13% 28% 25% 7%	840
December	1st to 10th	Night	23% 14% 37% 21% 5%	840
	11th to 20th	Night	26% 12% 33% 22% 6%	1029
	21st to end	Night	32% 15% 31% 19% 4	1155

Page generated at 2026-05-29 01:53:24. Version ac07

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