Hampton
Clear Sky Chart
History

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

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	20% 11% 3 7% 5% 4 4 3 5% 6% 32%	101580
	Night	20% 11% 3 8% 5% 4 4 3 5% 6% 31%	97561
Transparency	Day	52% 6% 12% 19% 10% 1	105112
	Night	53% 6% 11% 19% 10% 1	102105
Seeing	Day	30% 20% 29% 15% 5% 1	16562
	Night	28% 17% 29% 21% 5%	24303

By Month

Percentage Cloud Cover NE (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	11% 14% 5% 12% 6% 4 3 3 3 5% 34%	2207
	11th to 20th	Day	16% 13% 4 11% 5% 4 3 2 3 4 36%	2432
	21st to end	Day	14% 11% 4 9% 5% 5% 5% 4 6% 7% 33%	3124
February	1st to 10th	Day	17% 13% 5% 7% 6% 5% 4 4 5% 5% 29%	1710
	11th to 20th	Day	16% 15% 3 9% 6% 4 3 3 5% 7% 29%	1663
	21st to end	Day	12% 13% 4 7% 5% 5% 3 3 5% 6% 34%	1494
March	1st to 10th	Day	23% 18% 4 7% 4 3 3 3 4 4 28%	3334
	11th to 20th	Day	17% 23% 4 9% 5% 4 4 3 4 6% 23%	3480
	21st to end	Day	29% 14% 5% 8% 5% 3 4 3 4 4 22%	3816
April	1st to 10th	Day	23% 16% 4 7% 5% 4 4 3 4 4 26%	2206
	11th to 20th	Day	21% 12% 3 6% 4 3 3 3 5% 6% 34%	2442
	21st to end	Day	23% 11% 3 7% 3 4 3 3 5% 6% 31%	2470
May	1st to 10th	Day	21% 13% 4 9% 5% 4 4 4 4 6% 26%	4106
	11th to 20th	Day	18% 9% 2 8% 5% 5% 4 4 6% 7% 32%	4357
	21st to end	Day	17% 9% 3 7% 5% 5% 5% 5% 7% 8% 30%	4856
June	1st to 10th	Day	25% 11% 3 6% 4 4 5% 3 5% 6% 27%	2850
	11th to 20th	Day	21% 9% 3 6% 5% 4 4 3 5% 7% 34%	2850
	21st to end	Day	29% 9% 2 5% 4 4 4 3 5% 6% 27%	2850
July	1st to 10th	Day	18% 8% 3 7% 5% 5% 5% 4 6% 7% 31%	4760
	11th to 20th	Day	23% 8% 2 6% 4 4 4 3 6% 7% 34%	4760
	21st to end	Day	18% 8% 3 7% 5% 4 5% 3 6% 7% 33%	4517
August	1st to 10th	Day	23% 10% 3 6% 5% 4 5% 4 5% 6% 29%	4105
	11th to 20th	Day	16% 7% 3 7% 5% 4 5% 4 6% 9% 34%	4045
	21st to end	Day	14% 6% 2 5% 4 3 4 4 5% 9% 44%	4502
September	1st to 10th	Day	15% 7% 3 5% 3 4 5% 4 5% 8% 43%	2280
	11th to 20th	Day	18% 6% 2 6% 3 3 4 3 3 6% 46%	2097
	21st to end	Day	22% 6% 1 4 2 3 3 3 5% 6% 43%	2090
October	1st to 10th	Day	20% 8% 3 6% 4 4 3 3 5% 6% 40%	1910
	11th to 20th	Day	21% 10% 3 7% 3 4 4 3 4 6% 37%	1900
	21st to end	Day	20% 12% 3 7% 4 3 4 4 5% 7% 32%	2012
November	1st to 10th	Day	24% 10% 3 7% 4 3 3 3 4 5% 34%	1627
	11th to 20th	Day	18% 12% 3 7% 4 4 4 3 4 6% 34%	1520
	21st to end	Day	20% 14% 4 9% 4 4 4 3 4 4 29%	1520
December	1st to 10th	Day	25% 11% 4 9% 5% 4 3 3 5% 5% 25%	1520
	11th to 20th	Day	21% 15% 5% 10% 6% 4 3 3 4 4 24%	1737
	21st to end	Day	20% 10% 4 9% 6% 3 4 4 4 4 31%	2431
January	1st to 10th	Night	14% 11% 3 8% 5% 4 5% 4 5% 5% 36%	4748
	11th to 20th	Night	16% 13% 4 10% 5% 4 4 3 4 5% 32%	4524
	21st to end	Night	15% 13% 4 8% 6% 4 4 3 5% 6% 31%	4532
February	1st to 10th	Night	18% 12% 3 8% 5% 5% 4 3 6% 6% 30%	2470
	11th to 20th	Night	16% 13% 5% 9% 5% 5% 4 3 5% 5% 28%	2403
	21st to end	Night	14% 11% 5% 8% 7% 5% 4 3 4 6% 33%	1956
March	1st to 10th	Night	24% 15% 3 8% 4 6% 4 3 4 4 26%	3505
	11th to 20th	Night	17% 19% 5% 10% 6% 5% 4 3 4 6% 20%	3479
	21st to end	Night	30% 12% 4 7% 4 4 4 3 3 4 25%	3816
April	1st to 10th	Night	22% 15% 3 8% 5% 4 4 3 4 4 28%	1972
	11th to 20th	Night	23% 10% 3 6% 4 5% 3 3 5% 6% 33%	1688
	21st to end	Night	23% 11% 3 7% 5% 3 4 4 5% 6% 30%	1710
May	1st to 10th	Night	21% 14% 3 7% 5% 4 4 4 5% 6% 27%	2834
	11th to 20th	Night	19% 9% 2 6% 4 4 4 4 6% 6% 36%	2543
	21st to end	Night	18% 9% 3 7% 6% 5% 6% 4 6% 8% 29%	2749
June	1st to 10th	Night	26% 9% 3 8% 5% 4 4 3 5% 6% 26%	1339
	11th to 20th	Night	21% 10% 2 6% 5% 3 4 3 5% 6% 33%	1330
	21st to end	Night	29% 9% 2 6% 5% 4 4 3 4 5% 28%	1330
July	1st to 10th	Night	21% 11% 4 9% 5% 5% 5% 4 6% 6% 25%	2210
	11th to 20th	Night	24% 11% 3 7% 5% 5% 4 3 4 7% 27%	2210
	21st to end	Night	20% 8% 3 6% 4 4 5% 3 6% 8% 32%	3001
August	1st to 10th	Night	25% 11% 3 7% 4 4 4 4 4 6% 26%	2825
	11th to 20th	Night	15% 9% 3 7% 5% 5% 5% 4 7% 8% 31%	2782
	21st to end	Night	14% 6% 3 5% 4 4 4 3 6% 7% 44%	3153
September	1st to 10th	Night	18% 7% 2 6% 4 3 4 4 5% 7% 40%	1900
	11th to 20th	Night	20% 7% 2 5% 4 3 3 2 4 7% 43%	2080
	21st to end	Night	21% 6% 2 5% 4 4 4 4 5% 6% 41%	2090
October	1st to 10th	Night	20% 7% 2 6% 3 3 3 3 5% 8% 39%	2270
	11th to 20th	Night	16% 12% 3 6% 4 4 4 3 5% 6% 38%	2280
	21st to end	Night	22% 10% 3 7% 4 4 3 3 4 5% 33%	2584
November	1st to 10th	Night	21% 11% 3 7% 4 4 3 3 5% 6% 34%	2573
	11th to 20th	Night	20% 10% 3 8% 4 4 5% 3 5% 5% 32%	2660
	21st to end	Night	21% 11% 4 8% 5% 4 4 3 5% 6% 30%	2660
December	1st to 10th	Night	26% 12% 3 9% 5% 4 4 3 4 5% 25%	2660
	11th to 20th	Night	26% 13% 3 8% 5% 4 4 3 4 4 26%	3459
	21st to end	Night	22% 14% 5% 9% 4 3 3 2 3 4 30%	5236

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	54% 4 16% 17% 9%	2208
	11th to 20th	Day	52% 3 10% 23% 11% 1	2432
	21st to end	Day	48% 7% 15% 15% 15% 1	3124
February	1st to 10th	Day	55% 5% 11% 17% 10% 2	1710
	11th to 20th	Day	56% 4 12% 16% 10% 1	1671
	21st to end	Day	50% 5% 11% 21% 9% 3	1494
March	1st to 10th	Day	59% 4 9% 18% 6% 3	3338
	11th to 20th	Day	62% 5% 11% 13% 8% 1	3480
	21st to end	Day	67% 3 6% 12% 10% 2	3816
April	1st to 10th	Day	61% 5% 8% 13% 11% 3	2206
	11th to 20th	Day	52% 4 10% 20% 13% 1	2442
	21st to end	Day	54% 5% 10% 16% 12% 3	2470
May	1st to 10th	Day	58% 7% 11% 18% 7% 1	4120
	11th to 20th	Day	48% 7% 17% 19% 8% 1	4361
	21st to end	Day	49% 10% 15% 16% 10%	4856
June	1st to 10th	Day	58% 7% 10% 17% 8%	2850
	11th to 20th	Day	51% 5% 12% 20% 10% 1	2850
	21st to end	Day	58% 6% 11% 15% 9% 1	2850
July	1st to 10th	Day	51% 7% 13% 18% 10%	4685
	11th to 20th	Day	49% 6% 14% 23% 8%	4679
	21st to end	Day	49% 8% 13% 22% 7%	4372
August	1st to 10th	Day	55% 7% 11% 20% 6%	4092
	11th to 20th	Day	45% 8% 16% 24% 8%	4084
	21st to end	Day	36% 7% 15% 25% 17% 1	4502
September	1st to 10th	Day	40% 7% 13% 25% 14% 1	2280
	11th to 20th	Day	42% 4 12% 25% 14% 2	2097
	21st to end	Day	42% 6% 11% 25% 16% 1	2090
October	1st to 10th	Day	46% 6% 10% 27% 11%	3170
	11th to 20th	Day	48% 4 9% 30% 9%	3140
	21st to end	Day	42% 5% 16% 21% 17%	3288
November	1st to 10th	Day	55% 4 9% 21% 10% 1	1627
	11th to 20th	Day	51% 5% 13% 18% 12% 1	1520
	21st to end	Day	58% 5% 12% 18% 7%	1520
December	1st to 10th	Day	61% 5% 10% 17% 6% 1	1520
	11th to 20th	Day	62% 5% 10% 13% 9% 1	1737
	21st to end	Day	56% 4 16% 15% 8% 2	2431
January	1st to 10th	Night	48% 5% 13% 26% 6% 1	4748
	11th to 20th	Night	55% 5% 10% 20% 8% 1	4524
	21st to end	Night	52% 6% 11% 21% 10% 1	4532
February	1st to 10th	Night	54% 6% 12% 16% 12% 1	2470
	11th to 20th	Night	57% 5% 10% 16% 11% 2	2406
	21st to end	Night	53% 5% 10% 17% 12% 3	1956
March	1st to 10th	Night	61% 4 7% 17% 10% 1	3514
	11th to 20th	Night	64% 6% 9% 12% 8% 1	3480
	21st to end	Night	66% 3 6% 14% 10% 2	3816
April	1st to 10th	Night	59% 5% 8% 13% 11% 4	1972
	11th to 20th	Night	52% 4 11% 19% 13% 1	1688
	21st to end	Night	55% 5% 10% 15% 13% 2	1710
May	1st to 10th	Night	55% 10% 12% 15% 7% 1	2840
	11th to 20th	Night	46% 9% 17% 21% 6% 1	2544
	21st to end	Night	52% 11% 13% 17% 6% 1	2750
June	1st to 10th	Night	59% 6% 10% 17% 7% 1	1339
	11th to 20th	Night	51% 7% 12% 21% 8% 2	1330
	21st to end	Night	60% 7% 8% 15% 9% 1	1330
July	1st to 10th	Night	58% 7% 11% 12% 11%	2175
	11th to 20th	Night	57% 8% 9% 19% 7%	2168
	21st to end	Night	49% 8% 13% 19% 10% 1	2906
August	1st to 10th	Night	59% 7% 11% 17% 6%	2813
	11th to 20th	Night	47% 9% 16% 19% 8%	2809
	21st to end	Night	38% 7% 15% 23% 16% 1	3152
September	1st to 10th	Night	41% 8% 10% 26% 14% 1	1900
	11th to 20th	Night	43% 5% 13% 24% 15% 1	2080
	21st to end	Night	45% 5% 10% 25% 13% 2	2090
October	1st to 10th	Night	47% 5% 12% 23% 12% 1	3790
	11th to 20th	Night	42% 5% 11% 27% 16%	3779
	21st to end	Night	47% 4 13% 22% 14%	4245
November	1st to 10th	Night	52% 5% 12% 19% 11% 1	2573
	11th to 20th	Night	53% 5% 12% 18% 10% 1	2660
	21st to end	Night	55% 6% 15% 16% 8%	2660
December	1st to 10th	Night	61% 4 10% 17% 7%	2660
	11th to 20th	Night	62% 5% 9% 16% 9%	3460
	21st to end	Night	58% 5% 11% 18% 6% 2	5236

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	36% 24% 31% 9% 1	180
	11th to 20th	Day	43% 23% 25% 7% 2	185
	21st to end	Day	23% 25% 33% 14% 5%	407
February	1st to 10th	Day	34% 22% 25% 15% 4	370
	11th to 20th	Day	35% 28% 25% 10% 2 1	366
	21st to end	Day	29% 26% 28% 13% 3	346
March	1st to 10th	Day	31% 27% 29% 11% 2	460
	11th to 20th	Day	32% 24% 30% 10% 3 1	460
	21st to end	Day	40% 21% 25% 10% 3 1	506
April	1st to 10th	Day	42% 27% 21% 7% 3	460
	11th to 20th	Day	36% 27% 24% 9% 4	452
	21st to end	Day	36% 20% 28% 12% 4 1	460
May	1st to 10th	Day	38% 22% 26% 9% 4	463
	11th to 20th	Day	28% 20% 28% 18% 5%	646
	21st to end	Day	30% 19% 30% 16% 3 1	735
June	1st to 10th	Day	33% 20% 28% 15% 4	680
	11th to 20th	Day	27% 18% 31% 19% 5%	680
	21st to end	Day	34% 16% 25% 18% 6%	680
July	1st to 10th	Day	26% 14% 33% 20% 6% 1	670
	11th to 20th	Day	25% 12% 33% 21% 8% 1	668
	21st to end	Day	22% 15% 40% 18% 5% 1	562
August	1st to 10th	Day	23% 13% 38% 20% 5% 1	486
	11th to 20th	Day	24% 13% 36% 21% 6% 1	479
	21st to end	Day	22% 15% 32% 22% 7% 2	539
September	1st to 10th	Day	17% 18% 38% 19% 6% 1	490
	11th to 20th	Day	26% 17% 27% 21% 7% 2	490
	21st to end	Day	26% 19% 28% 18% 7% 3	490
October	1st to 10th	Day	25% 17% 24% 22% 10% 2	395
	11th to 20th	Day	27% 21% 26% 18% 6% 2	390
	21st to end	Day	30% 22% 29% 14% 4	429
November	1st to 10th	Day	32% 19% 28% 14% 5% 2	381
	11th to 20th	Day	34% 23% 23% 15% 5%	370
	21st to end	Day	33% 25% 29% 10% 2 1	370
December	1st to 10th	Day	36% 21% 27% 13% 3	370
	11th to 20th	Day	41% 27% 20% 11% 1	249
	21st to end	Day	35% 28% 26% 9% 1 1	198
January	1st to 10th	Night	30% 22% 26% 19% 2	850
	11th to 20th	Night	31% 21% 26% 17% 4	785
	21st to end	Night	23% 22% 33% 17% 5%	836
February	1st to 10th	Night	29% 22% 29% 17% 2	760
	11th to 20th	Night	29% 25% 26% 17% 2	743
	21st to end	Night	24% 22% 30% 21% 4	628
March	1st to 10th	Night	27% 21% 34% 17% 2	760
	11th to 20th	Night	28% 17% 30% 20% 4	760
	21st to end	Night	28% 21% 31% 14% 6%	836
April	1st to 10th	Night	35% 17% 30% 15% 3	648
	11th to 20th	Night	29% 18% 31% 18% 4	564
	21st to end	Night	31% 17% 30% 16% 5% 1	570
May	1st to 10th	Night	29% 16% 30% 20% 5% 1	570
	11th to 20th	Night	30% 15% 32% 18% 4 1	562
	21st to end	Night	25% 17% 37% 17% 4	616
June	1st to 10th	Night	31% 11% 27% 26% 5%	389
	11th to 20th	Night	24% 13% 28% 29% 6%	380
	21st to end	Night	31% 9% 26% 28% 6%	380
July	1st to 10th	Night	24% 6% 36% 27% 6%	370
	11th to 20th	Night	26% 7% 30% 30% 8%	368
	21st to end	Night	24% 8% 32% 31% 6%	594
August	1st to 10th	Night	20% 9% 33% 31% 8%	568
	11th to 20th	Night	25% 8% 28% 31% 8% 1	562
	21st to end	Night	19% 12% 27% 30% 11%	627
September	1st to 10th	Night	21% 9% 37% 25% 7% 1	570
	11th to 20th	Night	24% 10% 23% 27% 14% 1	750
	21st to end	Night	26% 12% 26% 26% 10%	760
October	1st to 10th	Night	25% 11% 26% 28% 10% 1	760
	11th to 20th	Night	25% 16% 30% 20% 9% 1	760
	21st to end	Night	31% 19% 27% 21% 3	836
November	1st to 10th	Night	30% 17% 25% 19% 7% 1	806
	11th to 20th	Night	29% 20% 26% 18% 6% 1	850
	21st to end	Night	30% 23% 25% 19% 4	850
December	1st to 10th	Night	34% 19% 27% 16% 3	850
	11th to 20th	Night	35% 23% 26% 13% 2	850
	21st to end	Night	33% 23% 24% 16% 4	935

Page generated at 2024-11-03 14:19:00. Version ac07

Copyright © 2024 Attilla Danko.