Huntington
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Huntington clear sky chart from 2005-11-06 to 2024-10-25.

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	14% 9% 4 8% 5% 4 4 4 5% 8% 35%	101014
	Night	15% 10% 4 8% 5% 4 4 3 5% 6% 36%	97817
Transparency	Day	48% 4 11% 23% 13% 1	100810
	Night	49% 3 10% 22% 13% 2	97692
Seeing	Day	18% 10% 26% 24% 16% 6%	15611
	Night	19% 9% 28% 30% 13% 1	25416

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	17% 15% 10% 12% 6% 4 4 3 4 5% 20%	2527
	11th to 20th	Day	16% 15% 9% 12% 6% 7% 6% 7% 5% 4 13%	2530
	21st to end	Day	27% 22% 9% 11% 4 3 3 2 3 3 13%	2910
February	1st to 10th	Day	17% 15% 5% 13% 7% 5% 4 3 4 5% 21%	1824
	11th to 20th	Day	16% 12% 4 11% 8% 5% 4 4 4 6% 26%	1848
	21st to end	Day	18% 15% 6% 9% 5% 4 3 3 4 6% 27%	1570
March	1st to 10th	Day	20% 19% 5% 8% 4 3 4 3 3 5% 26%	3120
	11th to 20th	Day	13% 10% 4 7% 4 4 4 4 6% 8% 37%	3407
	21st to end	Day	19% 12% 5% 9% 5% 4 5% 4 4 6% 27%	3909
April	1st to 10th	Day	16% 12% 4 8% 5% 5% 4 4 4 7% 31%	2280
	11th to 20th	Day	17% 9% 3 7% 5% 4 4 3 5% 8% 34%	2282
	21st to end	Day	20% 9% 3 6% 5% 4 4 4 5% 7% 33%	2470
May	1st to 10th	Day	20% 9% 2 7% 6% 5% 5% 4 6% 7% 29%	4082
	11th to 20th	Day	18% 6% 2 6% 4 5% 4 4 6% 9% 36%	4081
	21st to end	Day	10% 6% 2 6% 5% 5% 5% 5% 7% 9% 40%	4594
June	1st to 10th	Day	11% 5% 2 6% 5% 5% 5% 5% 7% 8% 41%	2660
	11th to 20th	Day	9% 5% 2 6% 5% 4 5% 4 6% 8% 45%	2660
	21st to end	Day	10% 6% 2 7% 6% 4 6% 5% 7% 10% 38%	2660
July	1st to 10th	Day	14% 6% 3 7% 5% 5% 5% 4 6% 9% 36%	4440
	11th to 20th	Day	7% 4 2 5% 4 4 5% 4 7% 11% 48%	4440
	21st to end	Day	8% 6% 3 7% 6% 5% 5% 5% 6% 9% 40%	4670
August	1st to 10th	Day	9% 5% 2 5% 4 4 5% 5% 7% 11% 44%	4104
	11th to 20th	Day	10% 4 2 6% 4 4 5% 4 7% 8% 46%	4017
	21st to end	Day	8% 4 2 6% 3 4 4 4 6% 10% 50%	4180
September	1st to 10th	Day	11% 6% 2 6% 5% 5% 5% 3 5% 7% 47%	2227
	11th to 20th	Day	10% 5% 2 5% 4 4 4 4 6% 9% 47%	2090
	21st to end	Day	14% 7% 3 5% 5% 4 4 3 5% 7% 43%	2090
October	1st to 10th	Day	13% 6% 2 6% 4 4 4 3 6% 7% 44%	2090
	11th to 20th	Day	15% 6% 3 5% 5% 5% 4 4 5% 7% 40%	1916
	21st to end	Day	20% 9% 3 9% 5% 4 5% 4 5% 6% 30%	1824
November	1st to 10th	Day	11% 7% 2 6% 3 4 4 3 5% 7% 49%	1672
	11th to 20th	Day	18% 12% 4 8% 4 4 4 3 5% 7% 31%	1710
	21st to end	Day	20% 14% 4 8% 4 4 4 3 4 6% 28%	1710
December	1st to 10th	Day	16% 17% 6% 11% 7% 5% 4 3 4 5% 23%	1710
	11th to 20th	Day	14% 17% 6% 11% 5% 5% 4 3 5% 6% 23%	1927
	21st to end	Day	24% 22% 9% 12% 6% 5% 4 2 3 4 11%	2783
January	1st to 10th	Night	18% 16% 8% 11% 5% 4 4 4 4 5% 21%	4428
	11th to 20th	Night	14% 20% 7% 16% 6% 5% 5% 4 4 4 15%	4440
	21st to end	Night	27% 17% 8% 10% 4 3 3 2 3 4 18%	4752
February	1st to 10th	Night	19% 15% 5% 10% 6% 4 4 3 4 5% 25%	2352
	11th to 20th	Night	12% 14% 4 9% 6% 5% 5% 3 4 7% 31%	2218
	21st to end	Night	19% 14% 4 9% 4 4 3 4 5% 5% 29%	1884
March	1st to 10th	Night	19% 13% 4 6% 5% 4 3 2 4 6% 35%	3733
	11th to 20th	Night	11% 7% 2 5% 4 5% 5% 4 6% 6% 45%	3551
	21st to end	Night	17% 10% 4 8% 5% 4 4 3 4 6% 35%	3736
April	1st to 10th	Night	15% 10% 3 6% 4 5% 4 3 5% 8% 36%	1900
	11th to 20th	Night	18% 8% 2 6% 5% 4 4 3 5% 6% 39%	1847
	21st to end	Night	19% 9% 3 6% 4 4 4 3 5% 5% 37%	1710
May	1st to 10th	Night	17% 9% 3 8% 5% 5% 5% 4 5% 8% 31%	2813
	11th to 20th	Night	20% 6% 2 5% 4 3 3 4 5% 8% 39%	2812
	21st to end	Night	11% 5% 2 6% 4 4 4 4 7% 7% 45%	2960
June	1st to 10th	Night	8% 5% 3 6% 4 4 4 4 5% 8% 48%	1520
	11th to 20th	Night	8% 5% 2 6% 4 4 4 4 6% 9% 47%	1520
	21st to end	Night	10% 4 2 6% 5% 4 6% 4 5% 9% 44%	1520
July	1st to 10th	Night	10% 5% 2 6% 4 4 4 4 6% 9% 46%	2530
	11th to 20th	Night	7% 3 1 5% 3 4 4 3 6% 9% 56%	2530
	21st to end	Night	10% 6% 2 7% 5% 4 4 4 7% 9% 42%	2886
August	1st to 10th	Night	12% 5% 2 6% 4 4 4 4 5% 8% 45%	2825
	11th to 20th	Night	9% 5% 2 5% 4 5% 4 3 6% 6% 49%	2808
	21st to end	Night	7% 4 2 6% 4 4 5% 3 6% 8% 52%	3476
September	1st to 10th	Night	10% 5% 2 5% 5% 3 4 3 5% 7% 52%	1933
	11th to 20th	Night	9% 4 1 4 3 4 3 3 5% 7% 56%	2090
	21st to end	Night	12% 7% 2 5% 4 4 4 3 5% 6% 48%	2090
October	1st to 10th	Night	11% 5% 2 4 3 4 4 4 4 8% 52%	2090
	11th to 20th	Night	17% 8% 2 6% 4 4 3 3 4 6% 43%	2259
	21st to end	Night	19% 9% 2 6% 4 3 4 3 5% 6% 37%	2638
November	1st to 10th	Night	12% 8% 3 6% 4 3 4 3 5% 7% 45%	2406
	11th to 20th	Night	15% 12% 3 7% 4 4 3 4 5% 7% 35%	2470
	21st to end	Night	19% 12% 4 8% 5% 5% 3 4 5% 6% 29%	2470
December	1st to 10th	Night	19% 13% 5% 8% 5% 5% 4 4 5% 6% 25%	2470
	11th to 20th	Night	17% 15% 8% 11% 6% 4 4 3 5% 5% 24%	3266
	21st to end	Night	26% 18% 7% 11% 5% 4 4 3 4 5% 14%	4884

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	69% 2 8% 16% 5%	2528
	11th to 20th	Day	75% 2 8% 8% 6%	2530
	21st to end	Day	79% 1 6% 11% 3	2910
February	1st to 10th	Day	67% 2 9% 14% 7% 1	1824
	11th to 20th	Day	60% 3 9% 20% 7% 1	1858
	21st to end	Day	59% 3 11% 18% 7% 2	1570
March	1st to 10th	Day	65% 1 7% 19% 8%	3120
	11th to 20th	Day	47% 2 10% 31% 9% 1	3407
	21st to end	Day	60% 2 15% 19% 3	3909
April	1st to 10th	Day	54% 3 10% 21% 12%	2280
	11th to 20th	Day	49% 4 10% 22% 12% 3	2282
	21st to end	Day	51% 2 12% 21% 12% 3	2470
May	1st to 10th	Day	55% 3 10% 23% 9%	4120
	11th to 20th	Day	47% 3 13% 27% 10% 1	4085
	21st to end	Day	40% 4 10% 26% 19% 2	4607
June	1st to 10th	Day	39% 5% 11% 26% 16% 3	2660
	11th to 20th	Day	36% 4 12% 26% 20% 3	2660
	21st to end	Day	40% 5% 14% 22% 15% 3	2660
July	1st to 10th	Day	44% 5% 11% 22% 16% 3	4371
	11th to 20th	Day	29% 5% 15% 31% 19% 1	4365
	21st to end	Day	39% 6% 14% 19% 19% 3	4522
August	1st to 10th	Day	33% 7% 16% 28% 15% 1	4091
	11th to 20th	Day	33% 5% 13% 31% 16% 1	4056
	21st to end	Day	30% 5% 13% 30% 19% 3	4179
September	1st to 10th	Day	37% 4 13% 24% 19% 3	2227
	11th to 20th	Day	35% 4 9% 28% 23% 2	2090
	21st to end	Day	40% 3 9% 26% 20% 1	2090
October	1st to 10th	Day	39% 4 10% 27% 18% 2	2090
	11th to 20th	Day	44% 3 10% 24% 19% 1	1916
	21st to end	Day	54% 4 10% 19% 11% 1	1824
November	1st to 10th	Day	36% 4 12% 27% 18% 1	1672
	11th to 20th	Day	54% 2 12% 19% 12% 2	1710
	21st to end	Day	58% 3 11% 19% 8% 1	1710
December	1st to 10th	Day	65% 2 12% 14% 6%	1710
	11th to 20th	Day	64% 2 9% 21% 3	1924
	21st to end	Day	81% 3 5% 7% 5%	2783
January	1st to 10th	Night	66% 3 9% 14% 7%	4428
	11th to 20th	Night	75% 1 7% 13% 4	4440
	21st to end	Night	72% 2 7% 15% 5%	4752
February	1st to 10th	Night	63% 2 10% 16% 8% 1	2352
	11th to 20th	Night	54% 3 10% 22% 10% 1	2219
	21st to end	Night	57% 3 10% 18% 10% 2	1884
March	1st to 10th	Night	54% 1 9% 25% 10% 1	3733
	11th to 20th	Night	40% 3 9% 30% 17% 2	3551
	21st to end	Night	53% 2 11% 26% 7% 1	3736
April	1st to 10th	Night	47% 4 11% 22% 15% 1	1900
	11th to 20th	Night	47% 3 8% 22% 16% 3	1847
	21st to end	Night	49% 3 9% 23% 13% 4	1710
May	1st to 10th	Night	54% 2 10% 23% 10% 2	2840
	11th to 20th	Night	46% 3 13% 28% 10% 1	2813
	21st to end	Night	38% 4 12% 24% 19% 3	2968
June	1st to 10th	Night	34% 4 10% 27% 21% 3	1520
	11th to 20th	Night	33% 5% 12% 26% 21% 3	1520
	21st to end	Night	35% 6% 16% 23% 16% 4	1520
July	1st to 10th	Night	35% 5% 13% 25% 17% 6%	2490
	11th to 20th	Night	25% 5% 16% 28% 24% 2	2482
	21st to end	Night	37% 6% 15% 17% 20% 4	2794
August	1st to 10th	Night	37% 5% 14% 30% 13% 1	2814
	11th to 20th	Night	34% 5% 12% 31% 17% 1	2835
	21st to end	Night	31% 5% 12% 27% 21% 3	3476
September	1st to 10th	Night	33% 4 12% 25% 20% 6%	1933
	11th to 20th	Night	29% 3 8% 31% 27% 3	2090
	21st to end	Night	37% 4 10% 25% 21% 3	2090
October	1st to 10th	Night	32% 4 10% 30% 22% 2	2090
	11th to 20th	Night	44% 3 7% 26% 19% 1	2259
	21st to end	Night	48% 3 8% 24% 15% 1	2638
November	1st to 10th	Night	40% 3 10% 25% 20% 2	2406
	11th to 20th	Night	49% 3 11% 21% 14% 2	2470
	21st to end	Night	57% 3 11% 21% 8%	2470
December	1st to 10th	Night	59% 3 11% 19% 8%	2470
	11th to 20th	Night	63% 3 10% 16% 7% 1	3268
	21st to end	Night	76% 2 9% 9% 4	4884

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	22% 17% 40% 16% 5% 1	270
	11th to 20th	Day	26% 15% 39% 15% 4 1	270
	21st to end	Day	30% 15% 32% 17% 6% 1	297
February	1st to 10th	Day	29% 18% 33% 16% 3	270
	11th to 20th	Day	26% 18% 36% 17% 4	270
	21st to end	Day	28% 18% 39% 13% 2	225
March	1st to 10th	Day	24% 23% 35% 15% 2 1	270
	11th to 20th	Day	27% 13% 32% 20% 8% 1	413
	21st to end	Day	32% 15% 26% 18% 6% 1	506
April	1st to 10th	Day	22% 13% 34% 21% 9% 2	460
	11th to 20th	Day	21% 19% 28% 19% 10% 3	452
	21st to end	Day	24% 15% 31% 18% 9% 2	460
May	1st to 10th	Day	25% 12% 30% 21% 8% 3	463
	11th to 20th	Day	23% 6% 26% 25% 13% 6%	487
	21st to end	Day	11% 6% 28% 27% 18% 9%	595
June	1st to 10th	Day	12% 8% 29% 29% 17% 6%	680
	11th to 20th	Day	12% 7% 26% 29% 20% 6%	680
	21st to end	Day	12% 7% 29% 26% 19% 7%	680
July	1st to 10th	Day	12% 3 18% 30% 23% 14%	671
	11th to 20th	Day	7% 4 22% 32% 21% 14%	668
	21st to end	Day	9% 5% 16% 32% 28% 11%	658
August	1st to 10th	Day	9% 3 14% 29% 26% 19%	486
	11th to 20th	Day	10% 5% 19% 27% 28% 12%	479
	21st to end	Day	8% 4 13% 28% 33% 14%	539
September	1st to 10th	Day	13% 5% 17% 27% 28% 11%	490
	11th to 20th	Day	9% 3 14% 25% 32% 17%	490
	21st to end	Day	18% 9% 20% 24% 22% 6%	490
October	1st to 10th	Day	12% 6% 26% 28% 20% 8%	490
	11th to 20th	Day	17% 17% 29% 25% 10% 2	444
	21st to end	Day	27% 16% 32% 21% 2 1	311
November	1st to 10th	Day	11% 13% 37% 23% 11% 4	270
	11th to 20th	Day	25% 17% 29% 17% 10% 1	270
	21st to end	Day	30% 14% 32% 20% 3	270
December	1st to 10th	Day	22% 24% 33% 14% 7%	270
	11th to 20th	Day	22% 16% 41% 14% 6%	270
	21st to end	Day	30% 22% 30% 16% 2	297
January	1st to 10th	Night	24% 16% 34% 21% 5% 1	950
	11th to 20th	Night	24% 15% 35% 21% 4	950
	21st to end	Night	24% 13% 35% 23% 4	965
February	1st to 10th	Night	28% 12% 33% 25% 4	760
	11th to 20th	Night	22% 13% 39% 23% 4	743
	21st to end	Night	28% 14% 35% 20% 3	628
March	1st to 10th	Night	22% 14% 32% 25% 7%	760
	11th to 20th	Night	19% 12% 36% 26% 7% 1	760
	21st to end	Night	25% 10% 32% 27% 5% 1	793
April	1st to 10th	Night	20% 11% 34% 29% 7% 1	570
	11th to 20th	Night	19% 11% 34% 28% 7% 1	563
	21st to end	Night	22% 8% 36% 25% 8% 1	570
May	1st to 10th	Night	22% 7% 33% 31% 8%	570
	11th to 20th	Night	22% 4 24% 32% 16% 1	561
	21st to end	Night	12% 4 23% 42% 18% 2	617
June	1st to 10th	Night	9% 3 23% 48% 17%	570
	11th to 20th	Night	10% 4 25% 39% 20% 2	570
	21st to end	Night	11% 3 23% 38% 23% 1	570
July	1st to 10th	Night	9% 2 15% 42% 28% 5%	555
	11th to 20th	Night	8% 3 13% 40% 32% 3	552
	21st to end	Night	7% 5% 12% 44% 31% 1	624
August	1st to 10th	Night	8% 2 12% 41% 32% 5%	567
	11th to 20th	Night	10% 3 13% 40% 31% 3	564
	21st to end	Night	7% 2 15% 35% 37% 4	627
September	1st to 10th	Night	12% 3 14% 35% 32% 4	603
	11th to 20th	Night	11% 2 14% 37% 32% 4	760
	21st to end	Night	15% 6% 22% 34% 20% 3	760
October	1st to 10th	Night	14% 5% 24% 33% 20% 4	760
	11th to 20th	Night	21% 13% 26% 28% 11% 1	760
	21st to end	Night	25% 11% 31% 25% 8%	812
November	1st to 10th	Night	17% 10% 34% 25% 13% 1	740
	11th to 20th	Night	21% 14% 32% 26% 6%	760
	21st to end	Night	26% 11% 29% 26% 7%	760
December	1st to 10th	Night	25% 14% 33% 22% 6%	760
	11th to 20th	Night	25% 13% 33% 24% 5%	937
	21st to end	Night	32% 13% 31% 21% 3	1045

Page generated at 2024-10-22 20:21:01. Version ac07

Copyright © 2024 Attilla Danko.