Gambridge Go-Karts
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Gambridge Go-Karts clear sky chart from 2005-11-06 to 2024-11-08.

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% 10% 3 8% 5% 5% 5% 4 6% 7% 34%	101930
	Night	15% 11% 4 9% 5% 5% 4 3 5% 6% 31%	97153
Transparency	Day	48% 7% 13% 21% 10% 1	105531
	Night	51% 7% 12% 19% 10% 1	101641
Seeing	Day	18% 10% 27% 26% 14% 4	14738
	Night	20% 9% 30% 28% 11% 1	23724

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	15% 16% 7% 12% 6% 5% 4 3 4 3 24%	2517
	11th to 20th	Day	10% 17% 7% 16% 9% 7% 5% 3 5% 5% 15%	2660
	21st to end	Day	17% 20% 6% 11% 6% 5% 4 3 4 5% 17%	3124
February	1st to 10th	Day	12% 16% 5% 12% 8% 6% 5% 4 5% 5% 22%	1710
	11th to 20th	Day	11% 14% 6% 12% 5% 5% 4 4 5% 7% 26%	1663
	21st to end	Day	15% 15% 5% 10% 6% 6% 4 3 6% 6% 23%	1444
March	1st to 10th	Day	17% 11% 3 10% 6% 4 4 3 5% 5% 31%	3432
	11th to 20th	Day	10% 13% 6% 10% 7% 5% 6% 4 5% 5% 28%	3480
	21st to end	Day	14% 8% 2 7% 5% 4 4 4 5% 6% 41%	3815
April	1st to 10th	Day	18% 10% 3 9% 5% 5% 4 3 4 6% 31%	2261
	11th to 20th	Day	19% 9% 3 6% 5% 4 4 3 5% 6% 37%	2325
	21st to end	Day	18% 10% 3 8% 5% 4 3 3 4 6% 36%	2470
May	1st to 10th	Day	16% 7% 3 7% 6% 5% 5% 4 6% 7% 34%	4164
	11th to 20th	Day	15% 9% 2 7% 4 5% 4 4 6% 8% 37%	4398
	21st to end	Day	14% 7% 2 6% 4 4 4 3 5% 7% 45%	4837
June	1st to 10th	Day	16% 7% 2 6% 4 5% 5% 4 6% 8% 37%	2660
	11th to 20th	Day	13% 5% 2 6% 4 4 5% 5% 7% 9% 40%	2704
	21st to end	Day	15% 6% 2 7% 5% 4 4 4 6% 8% 38%	2850
July	1st to 10th	Day	10% 5% 2 6% 5% 5% 5% 5% 8% 10% 39%	4610
	11th to 20th	Day	10% 5% 2 6% 4 4 5% 4 6% 8% 46%	4440
	21st to end	Day	8% 5% 2 6% 5% 4 6% 5% 6% 9% 45%	4607
August	1st to 10th	Day	13% 8% 3 7% 4 4 4 4 7% 8% 39%	4104
	11th to 20th	Day	13% 7% 2 6% 4 4 5% 4 7% 10% 38%	4044
	21st to end	Day	8% 6% 3 6% 4 4 4 4 7% 9% 45%	4352
September	1st to 10th	Day	13% 7% 2 6% 5% 5% 5% 3 6% 7% 43%	2280
	11th to 20th	Day	11% 6% 2 5% 4 4 4 3 5% 8% 47%	2192
	21st to end	Day	15% 7% 3 7% 5% 5% 5% 4 5% 6% 38%	2038
October	1st to 10th	Day	19% 8% 4 8% 4 4 4 3 5% 6% 34%	1900
	11th to 20th	Day	22% 11% 3 8% 5% 3 4 3 6% 6% 28%	1900
	21st to end	Day	25% 12% 4 9% 5% 5% 4 4 5% 5% 23%	2090
November	1st to 10th	Day	16% 12% 4 8% 5% 5% 6% 4 5% 7% 28%	1621
	11th to 20th	Day	16% 16% 4 9% 5% 4 5% 6% 6% 6% 22%	1520
	21st to end	Day	20% 18% 5% 9% 7% 5% 5% 3 5% 7% 17%	1520
December	1st to 10th	Day	17% 20% 6% 15% 7% 6% 4 4 4 6% 13%	1520
	11th to 20th	Day	18% 16% 5% 9% 6% 6% 4 3 5% 6% 22%	1906
	21st to end	Day	26% 17% 5% 14% 5% 4 4 3 4 4 14%	2772
January	1st to 10th	Night	16% 20% 6% 14% 8% 5% 5% 3 4 5% 14%	4429
	11th to 20th	Night	13% 13% 8% 17% 10% 6% 5% 3 4 5% 16%	4298
	21st to end	Night	18% 17% 7% 11% 6% 5% 4 3 4 5% 19%	4532
February	1st to 10th	Night	13% 16% 6% 13% 8% 6% 5% 4 4 6% 19%	2470
	11th to 20th	Night	13% 15% 6% 11% 6% 5% 5% 4 5% 5% 26%	2403
	21st to end	Night	14% 14% 5% 11% 5% 5% 4 4 6% 6% 26%	2005
March	1st to 10th	Night	17% 11% 4 8% 5% 5% 4 3 5% 6% 31%	3408
	11th to 20th	Night	13% 14% 6% 11% 5% 5% 4 3 4 5% 31%	3479
	21st to end	Night	15% 7% 4 7% 5% 4 4 4 6% 6% 36%	3817
April	1st to 10th	Night	20% 10% 3 8% 5% 4 4 4 5% 6% 30%	1919
	11th to 20th	Night	18% 8% 3 7% 5% 3 3 4 6% 7% 36%	1820
	21st to end	Night	17% 8% 3 9% 6% 4 4 4 5% 6% 34%	1710
May	1st to 10th	Night	17% 7% 3 7% 4 4 4 3 6% 6% 38%	2774
	11th to 20th	Night	15% 7% 2 6% 4 4 5% 4 6% 7% 39%	2495
	21st to end	Night	11% 6% 2 5% 4 4 4 3 5% 8% 48%	2738
June	1st to 10th	Night	15% 7% 3 6% 5% 5% 5% 4 5% 7% 39%	1520
	11th to 20th	Night	10% 5% 2 6% 4 4 5% 5% 7% 9% 44%	1467
	21st to end	Night	12% 9% 3 6% 6% 3 5% 4 5% 7% 40%	1330
July	1st to 10th	Night	7% 4 2 7% 5% 5% 4 4 6% 7% 49%	2334
	11th to 20th	Night	13% 6% 2 4 3 3 4 3 5% 8% 48%	2520
	21st to end	Night	9% 5% 2 5% 4 4 5% 4 6% 9% 48%	2943
August	1st to 10th	Night	9% 6% 3 5% 4 5% 5% 3 5% 8% 47%	2825
	11th to 20th	Night	12% 7% 3 6% 3 3 4 3 5% 8% 45%	2785
	21st to end	Night	11% 6% 2 6% 4 4 5% 3 6% 9% 45%	3271
September	1st to 10th	Night	11% 5% 3 5% 4 4 5% 4 5% 8% 45%	1900
	11th to 20th	Night	12% 5% 2 5% 4 3 3 3 5% 7% 51%	1985
	21st to end	Night	16% 7% 3 6% 5% 4 4 3 5% 6% 41%	2142
October	1st to 10th	Night	18% 8% 2 7% 5% 5% 4 4 5% 6% 35%	2280
	11th to 20th	Night	21% 12% 3 8% 6% 5% 5% 3 4 5% 29%	2280
	21st to end	Night	22% 11% 4 8% 5% 5% 5% 4 5% 6% 25%	2508
November	1st to 10th	Night	19% 12% 3 7% 4 4 5% 3 5% 6% 32%	2614
	11th to 20th	Night	17% 17% 5% 8% 6% 5% 5% 3 6% 6% 24%	2660
	21st to end	Night	20% 16% 4 10% 6% 5% 6% 4 5% 6% 17%	2660
December	1st to 10th	Night	20% 21% 7% 11% 6% 4 4 3 5% 5% 14%	2660
	11th to 20th	Night	16% 19% 6% 13% 6% 4 5% 4 5% 5% 18%	3288
	21st to end	Night	26% 19% 6% 14% 6% 5% 4 3 3 4 11%	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	63% 7% 14% 10% 6%	2518
	11th to 20th	Day	71% 6% 10% 8% 5%	2660
	21st to end	Day	68% 7% 10% 8% 5% 1	3124
February	1st to 10th	Day	64% 5% 11% 15% 4 1	1710
	11th to 20th	Day	58% 7% 10% 15% 8% 1	1672
	21st to end	Day	61% 6% 11% 15% 7%	1444
March	1st to 10th	Day	52% 9% 14% 14% 10%	3435
	11th to 20th	Day	52% 8% 14% 17% 8% 1	3480
	21st to end	Day	42% 7% 11% 21% 17% 2	3815
April	1st to 10th	Day	54% 6% 9% 19% 11% 1	2261
	11th to 20th	Day	48% 6% 10% 21% 15% 1	2325
	21st to end	Day	51% 6% 10% 18% 13% 3	2470
May	1st to 10th	Day	45% 8% 13% 21% 12% 1	4176
	11th to 20th	Day	44% 8% 14% 23% 11% 1	4402
	21st to end	Day	38% 7% 14% 22% 16% 3	4837
June	1st to 10th	Day	45% 7% 13% 22% 13%	2660
	11th to 20th	Day	39% 8% 14% 24% 14% 1	2704
	21st to end	Day	43% 8% 14% 23% 12% 1	2850
July	1st to 10th	Day	39% 6% 17% 24% 13% 1	4540
	11th to 20th	Day	35% 5% 16% 33% 9% 1	4365
	21st to end	Day	35% 7% 12% 32% 13%	4460
August	1st to 10th	Day	43% 6% 15% 25% 11% 1	4091
	11th to 20th	Day	41% 7% 17% 26% 9%	4083
	21st to end	Day	36% 5% 14% 34% 11% 1	4352
September	1st to 10th	Day	40% 7% 14% 27% 10% 1	2280
	11th to 20th	Day	36% 6% 15% 30% 13% 1	2192
	21st to end	Day	45% 8% 13% 24% 9%	2038
October	1st to 10th	Day	45% 5% 12% 27% 10% 1	3160
	11th to 20th	Day	47% 5% 16% 22% 11%	3140
	21st to end	Day	55% 6% 15% 18% 6%	3428
November	1st to 10th	Day	53% 9% 14% 16% 7% 1	1621
	11th to 20th	Day	59% 9% 13% 12% 6% 1	1520
	21st to end	Day	64% 9% 12% 12% 3	1520
December	1st to 10th	Day	73% 7% 10% 8% 2	1520
	11th to 20th	Day	64% 8% 12% 10% 6%	1906
	21st to end	Day	73% 6% 9% 8% 3	2772
January	1st to 10th	Night	69% 8% 10% 10% 3	4429
	11th to 20th	Night	67% 8% 11% 10% 4 1	4298
	21st to end	Night	65% 7% 12% 10% 5% 1	4532
February	1st to 10th	Night	66% 6% 9% 16% 3 1	2470
	11th to 20th	Night	58% 7% 11% 17% 7%	2405
	21st to end	Night	56% 6% 13% 17% 7%	2005
March	1st to 10th	Night	52% 6% 12% 19% 9% 1	3418
	11th to 20th	Night	51% 8% 15% 17% 7% 1	3480
	21st to end	Night	42% 8% 12% 21% 15% 1	3817
April	1st to 10th	Night	55% 5% 9% 19% 11% 1	1919
	11th to 20th	Night	47% 5% 9% 21% 16% 2	1820
	21st to end	Night	50% 6% 12% 14% 16% 2	1710
May	1st to 10th	Night	44% 7% 14% 17% 17% 2	2781
	11th to 20th	Night	41% 8% 15% 22% 12% 2	2496
	21st to end	Night	32% 8% 14% 25% 18% 2	2739
June	1st to 10th	Night	42% 7% 12% 23% 14% 2	1520
	11th to 20th	Night	35% 7% 14% 24% 20% 1	1467
	21st to end	Night	44% 6% 13% 22% 14% 1	1330
July	1st to 10th	Night	34% 4 17% 25% 18% 2	2295
	11th to 20th	Night	34% 5% 13% 33% 15%	2472
	21st to end	Night	32% 6% 13% 32% 16% 1	2849
August	1st to 10th	Night	37% 5% 15% 25% 17% 1	2814
	11th to 20th	Night	37% 5% 17% 27% 13% 1	2812
	21st to end	Night	37% 5% 11% 33% 12% 1	3271
September	1st to 10th	Night	35% 8% 15% 28% 12% 1	1900
	11th to 20th	Night	32% 7% 13% 31% 16% 1	1985
	21st to end	Night	43% 6% 12% 28% 10%	2142
October	1st to 10th	Night	38% 6% 10% 27% 19%	3800
	11th to 20th	Night	47% 5% 15% 24% 9%	3779
	21st to end	Night	51% 6% 14% 23% 6%	4120
November	1st to 10th	Night	52% 7% 13% 20% 8%	2614
	11th to 20th	Night	59% 8% 12% 13% 6% 2	2660
	21st to end	Night	65% 10% 13% 10% 2	2660
December	1st to 10th	Night	70% 9% 10% 9% 3	2660
	11th to 20th	Night	67% 7% 12% 11% 3	3288
	21st to end	Night	78% 5% 7% 8% 2	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	18% 19% 37% 14% 11% 1	180
	11th to 20th	Day	19% 17% 37% 18% 8% 1	222
	21st to end	Day	24% 13% 32% 24% 7%	297
February	1st to 10th	Day	21% 21% 37% 16% 5%	270
	11th to 20th	Day	17% 19% 40% 21% 3	270
	21st to end	Day	25% 24% 26% 24%	247
March	1st to 10th	Day	19% 11% 40% 25% 5%	460
	11th to 20th	Day	17% 17% 36% 24% 7%	460
	21st to end	Day	26% 10% 33% 21% 8% 1	506
April	1st to 10th	Day	20% 11% 35% 23% 9% 1	460
	11th to 20th	Day	26% 14% 25% 20% 12% 3	452
	21st to end	Day	21% 13% 28% 26% 9% 3	460
May	1st to 10th	Day	22% 8% 26% 27% 13% 4	463
	11th to 20th	Day	18% 4 26% 30% 17% 4	487
	21st to end	Day	16% 6% 24% 31% 17% 6%	529
June	1st to 10th	Day	19% 7% 24% 32% 15% 2	490
	11th to 20th	Day	16% 7% 23% 33% 16% 6%	534
	21st to end	Day	17% 7% 26% 34% 13% 3	680
July	1st to 10th	Day	11% 5% 21% 36% 22% 6%	590
	11th to 20th	Day	13% 5% 20% 31% 23% 7%	484
	21st to end	Day	8% 3 23% 38% 20% 8%	532
August	1st to 10th	Day	13% 4 18% 33% 25% 8%	486
	11th to 20th	Day	13% 3 18% 29% 28% 9%	479
	21st to end	Day	12% 6% 22% 30% 23% 7%	539
September	1st to 10th	Day	12% 9% 22% 28% 21% 9%	490
	11th to 20th	Day	11% 3 18% 28% 26% 14%	490
	21st to end	Day	16% 10% 25% 26% 18% 6%	490
October	1st to 10th	Day	20% 10% 29% 21% 14% 6%	490
	11th to 20th	Day	23% 17% 30% 21% 7% 2	490
	21st to end	Day	30% 15% 29% 19% 7%	539
November	1st to 10th	Day	26% 17% 26% 24% 7%	254
	11th to 20th	Day	23% 20% 33% 18% 4 2	180
	21st to end	Day	25% 20% 38% 16% 2	180
December	1st to 10th	Day	23% 21% 33% 20% 3	180
	11th to 20th	Day	23% 26% 31% 16% 3 1	180
	21st to end	Day	27% 19% 38% 13% 3	198
January	1st to 10th	Night	23% 15% 35% 19% 6% 1	760
	11th to 20th	Night	26% 12% 33% 23% 6% 1	760
	21st to end	Night	21% 8% 32% 30% 7% 1	836
February	1st to 10th	Night	20% 10% 39% 27% 4	760
	11th to 20th	Night	19% 11% 38% 27% 5% 1	743
	21st to end	Night	20% 13% 38% 25% 4	628
March	1st to 10th	Night	20% 11% 36% 28% 5%	760
	11th to 20th	Night	17% 12% 38% 28% 5% 1	760
	21st to end	Night	19% 8% 32% 30% 10%	836
April	1st to 10th	Night	25% 8% 33% 28% 6%	760
	11th to 20th	Night	20% 10% 30% 29% 10% 1	696
	21st to end	Night	19% 8% 31% 30% 11%	570
May	1st to 10th	Night	22% 2 24% 34% 16% 2	537
	11th to 20th	Night	14% 6% 26% 40% 12% 1	374
	21st to end	Night	11% 5% 23% 41% 20%	411
June	1st to 10th	Night	17% 4 29% 36% 13% 1	380
	11th to 20th	Night	11% 5% 26% 42% 16% 1	380
	21st to end	Night	16% 5% 22% 38% 18% 1	380
July	1st to 10th	Night	8% 4 19% 45% 22% 1	370
	11th to 20th	Night	11% 5% 21% 36% 25% 1	368
	21st to end	Night	10% 2 20% 45% 23% 1	532
August	1st to 10th	Night	10% 3 18% 37% 31% 2	567
	11th to 20th	Night	9% 2 20% 35% 31% 3	564
	21st to end	Night	13% 3 22% 35% 25% 2	709
September	1st to 10th	Night	13% 4 24% 33% 20% 5%	760
	11th to 20th	Night	14% 4 19% 32% 25% 7%	760
	21st to end	Night	19% 8% 19% 31% 18% 5%	760
October	1st to 10th	Night	20% 8% 29% 26% 15% 2	760
	11th to 20th	Night	24% 13% 30% 23% 9% 1	760
	21st to end	Night	29% 12% 31% 23% 4	836
November	1st to 10th	Night	25% 12% 29% 24% 10%	771
	11th to 20th	Night	25% 15% 35% 18% 6% 1	760
	21st to end	Night	27% 14% 31% 22% 5%	760
December	1st to 10th	Night	30% 18% 33% 16% 4	760
	11th to 20th	Night	23% 16% 38% 18% 4 1	760
	21st to end	Night	30% 14% 35% 20% 2	836

Page generated at 2024-11-05 08:15:50. Version ac07

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