Caledonia
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Caledonia clear sky chart from 2005-11-06 to 2024-12-09.

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% 3 8% 5% 4 4 4 6% 7% 37%	101689
	Night	14% 10% 4 8% 4 4 4 3 5% 6% 38%	98172
Transparency	Day	44% 7% 12% 23% 13% 1	105241
	Night	44% 6% 11% 22% 14% 2	102761
Seeing	Day	16% 11% 29% 25% 14% 5%	15963
	Night	17% 9% 31% 30% 11% 1	25848

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	12% 14% 10% 14% 6% 4 5% 3 4 4 25%	2527
	11th to 20th	Day	12% 12% 6% 16% 5% 4 5% 8% 7% 5% 19%	2530
	21st to end	Day	17% 18% 9% 12% 5% 4 4 3 5% 5% 19%	2911
February	1st to 10th	Day	12% 14% 5% 9% 5% 5% 6% 4 5% 6% 28%	1710
	11th to 20th	Day	14% 10% 3 7% 7% 5% 4 3 5% 6% 37%	1826
	21st to end	Day	13% 13% 4 11% 5% 4 4 3 6% 6% 32%	1570
March	1st to 10th	Day	13% 10% 4 8% 5% 4 4 3 5% 5% 40%	3120
	11th to 20th	Day	11% 6% 3 7% 5% 4 4 4 6% 7% 41%	3310
	21st to end	Day	21% 13% 5% 11% 5% 5% 4 4 5% 5% 21%	4155
April	1st to 10th	Day	18% 12% 3 9% 5% 5% 4 4 4 5% 31%	2280
	11th to 20th	Day	16% 10% 3 7% 5% 4 5% 5% 5% 6% 34%	2254
	21st to end	Day	19% 9% 3 8% 5% 4 4 4 5% 6% 32%	2352
May	1st to 10th	Day	16% 8% 3 8% 5% 5% 5% 4 5% 7% 36%	4113
	11th to 20th	Day	15% 7% 2 5% 4 4 4 3 5% 7% 43%	4399
	21st to end	Day	12% 6% 2 6% 5% 4 5% 5% 7% 9% 39%	4824
June	1st to 10th	Day	10% 5% 2 6% 5% 4 4 5% 5% 9% 44%	2660
	11th to 20th	Day	10% 6% 2 5% 4 4 4 4 7% 9% 45%	2660
	21st to end	Day	11% 6% 2 7% 5% 4 5% 4 7% 10% 37%	2660
July	1st to 10th	Day	11% 8% 3 8% 5% 5% 5% 5% 8% 9% 33%	4440
	11th to 20th	Day	6% 4 2 5% 4 4 5% 4 6% 10% 50%	4440
	21st to end	Day	8% 7% 2 7% 6% 5% 5% 4 6% 9% 41%	4813
August	1st to 10th	Day	10% 6% 2 5% 4 4 5% 5% 7% 9% 42%	4371
	11th to 20th	Day	11% 4 2 5% 4 4 5% 4 7% 9% 45%	3738
	21st to end	Day	9% 6% 2 5% 4 4 5% 3 6% 8% 47%	4180
September	1st to 10th	Day	12% 6% 2 6% 4 4 4 3 5% 9% 47%	2280
	11th to 20th	Day	13% 4 2 4 3 3 4 3 6% 8% 51%	2195
	21st to end	Day	12% 7% 2 7% 4 4 4 3 6% 7% 44%	2090
October	1st to 10th	Day	13% 7% 3 5% 4 4 3 3 5% 6% 48%	1981
	11th to 20th	Day	19% 9% 3 6% 4 4 4 4 5% 7% 35%	1900
	21st to end	Day	19% 10% 3 6% 5% 4 3 2 4 5% 37%	1900
November	1st to 10th	Day	13% 8% 3 6% 4 3 4 3 4 6% 44%	1762
	11th to 20th	Day	14% 12% 5% 10% 5% 4 5% 3 5% 6% 31%	1800
	21st to end	Day	16% 13% 4 9% 5% 3 2 3 4 5% 35%	1653
December	1st to 10th	Day	14% 14% 4 9% 6% 4 5% 3 4 5% 31%	1584
	11th to 20th	Day	13% 13% 5% 10% 6% 5% 5% 4 5% 6% 28%	1918
	21st to end	Day	20% 20% 9% 14% 6% 4 3 2 3 3 14%	2783
January	1st to 10th	Night	12% 14% 8% 12% 6% 4 3 2 4 4 30%	4428
	11th to 20th	Night	14% 17% 7% 14% 6% 4 4 6% 6% 3 20%	4440
	21st to end	Night	18% 17% 7% 11% 5% 5% 4 3 4 6% 20%	4752
February	1st to 10th	Night	13% 15% 4 8% 6% 5% 4 3 5% 5% 32%	2470
	11th to 20th	Night	13% 11% 4 6% 5% 5% 4 3 5% 6% 38%	2238
	21st to end	Night	17% 13% 4 8% 4 3 3 3 5% 6% 35%	1884
March	1st to 10th	Night	18% 10% 3 5% 4 4 3 3 4 5% 41%	3733
	11th to 20th	Night	9% 6% 2 6% 4 5% 5% 4 5% 7% 46%	3678
	21st to end	Night	24% 12% 4 9% 5% 4 4 2 4 5% 28%	3476
April	1st to 10th	Night	17% 11% 3 6% 4 4 4 3 4 6% 38%	1900
	11th to 20th	Night	18% 10% 3 7% 5% 4 3 2 4 5% 39%	1875
	21st to end	Night	17% 9% 2 6% 4 4 4 3 6% 7% 37%	1826
May	1st to 10th	Night	16% 6% 3 7% 5% 5% 4 4 5% 7% 37%	2767
	11th to 20th	Night	13% 6% 3 6% 4 4 5% 4 7% 7% 40%	2506
	21st to end	Night	10% 8% 2 6% 4 4 4 3 7% 8% 43%	2743
June	1st to 10th	Night	8% 4 1 5% 5% 5% 5% 5% 6% 7% 47%	1520
	11th to 20th	Night	10% 6% 2 5% 4 4 5% 4 5% 10% 46%	1520
	21st to end	Night	9% 7% 3 6% 5% 4 4 4 4 9% 44%	1520
July	1st to 10th	Night	15% 7% 2 7% 4 5% 5% 4 6% 7% 39%	2530
	11th to 20th	Night	5% 4 2 4 4 4 4 5% 7% 8% 54%	2530
	21st to end	Night	6% 6% 3 6% 5% 5% 5% 5% 7% 8% 45%	2750
August	1st to 10th	Night	6% 5% 2 5% 4 4 4 4 6% 9% 52%	2566
	11th to 20th	Night	9% 5% 2 5% 4 4 5% 4 6% 7% 50%	3090
	21st to end	Night	8% 5% 1 4 4 4 4 4 5% 9% 51%	3476
September	1st to 10th	Night	9% 6% 2 7% 3 3 3 2 5% 5% 55%	1900
	11th to 20th	Night	11% 4 1 4 4 4 4 2 5% 7% 54%	1966
	21st to end	Night	11% 6% 2 6% 4 4 4 3 5% 7% 49%	2090
October	1st to 10th	Night	11% 6% 2 6% 3 4 3 3 4 6% 51%	2197
	11th to 20th	Night	17% 7% 2 6% 3 4 3 3 4 6% 44%	2280
	21st to end	Night	20% 9% 3 6% 3 4 4 3 5% 6% 38%	2698
November	1st to 10th	Night	13% 7% 2 6% 3 3 3 2 5% 6% 48%	2536
	11th to 20th	Night	15% 11% 3 8% 5% 4 4 4 5% 6% 36%	2600
	21st to end	Night	17% 12% 4 8% 5% 3 3 3 4 5% 36%	2745
December	1st to 10th	Night	14% 12% 4 9% 5% 5% 5% 3 5% 7% 31%	2779
	11th to 20th	Night	15% 14% 4 9% 5% 5% 4 3 5% 5% 31%	3279
	21st to end	Night	22% 17% 6% 10% 5% 4 5% 4 5% 5% 17%	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	62% 6% 11% 15% 6%	2528
	11th to 20th	Day	61% 7% 12% 12% 8%	2530
	21st to end	Day	68% 4 9% 14% 5%	2911
February	1st to 10th	Day	55% 6% 13% 15% 9% 1	1710
	11th to 20th	Day	49% 5% 11% 24% 10% 1	1836
	21st to end	Day	54% 6% 8% 21% 9% 2	1570
March	1st to 10th	Day	44% 8% 11% 24% 10% 3	3120
	11th to 20th	Day	39% 7% 11% 31% 11% 1	3310
	21st to end	Day	62% 9% 12% 13% 4 1	4155
April	1st to 10th	Day	54% 6% 10% 21% 9%	2280
	11th to 20th	Day	49% 7% 9% 22% 11% 2	2254
	21st to end	Day	51% 6% 12% 17% 13% 1	2352
May	1st to 10th	Day	46% 7% 11% 21% 14% 1	4151
	11th to 20th	Day	40% 7% 11% 28% 14%	4403
	21st to end	Day	38% 9% 12% 21% 16% 4	4837
June	1st to 10th	Day	36% 8% 13% 26% 16% 1	2660
	11th to 20th	Day	34% 8% 13% 24% 19% 2	2660
	21st to end	Day	39% 9% 14% 22% 13% 2	2660
July	1st to 10th	Day	43% 8% 14% 24% 9% 2	4371
	11th to 20th	Day	27% 7% 18% 29% 18% 1	4365
	21st to end	Day	38% 9% 14% 17% 19% 3	4662
August	1st to 10th	Day	35% 9% 15% 28% 12% 1	4356
	11th to 20th	Day	33% 8% 14% 32% 13% 1	3774
	21st to end	Day	34% 7% 13% 28% 17% 2	4179
September	1st to 10th	Day	35% 7% 11% 26% 18% 2	2280
	11th to 20th	Day	31% 5% 12% 31% 19% 2	2195
	21st to end	Day	39% 5% 9% 29% 17% 1	2090
October	1st to 10th	Day	24% 4 7% 37% 27% 1	3293
	11th to 20th	Day	33% 5% 11% 26% 24% 1	3140
	21st to end	Day	43% 4 8% 28% 14% 3	3112
November	1st to 10th	Day	41% 6% 14% 24% 15% 1	1762
	11th to 20th	Day	54% 5% 12% 19% 9% 1	1800
	21st to end	Day	53% 4 13% 22% 8%	1653
December	1st to 10th	Day	54% 5% 15% 17% 8% 1	1584
	11th to 20th	Day	56% 5% 15% 16% 7% 2	1915
	21st to end	Day	75% 5% 7% 8% 4	2783
January	1st to 10th	Night	58% 5% 9% 19% 8% 1	4428
	11th to 20th	Night	65% 5% 9% 12% 8%	4440
	21st to end	Night	67% 5% 9% 13% 5% 1	4752
February	1st to 10th	Night	54% 4 10% 18% 12% 1	2470
	11th to 20th	Night	47% 4 11% 22% 14% 1	2239
	21st to end	Night	50% 6% 10% 20% 11% 4	1884
March	1st to 10th	Night	45% 6% 13% 22% 10% 5%	3733
	11th to 20th	Night	35% 7% 11% 29% 16% 2	3678
	21st to end	Night	59% 6% 8% 18% 8% 1	3476
April	1st to 10th	Night	46% 6% 11% 21% 14% 2	1900
	11th to 20th	Night	47% 5% 6% 20% 18% 4	1875
	21st to end	Night	45% 6% 12% 23% 12% 2	1826
May	1st to 10th	Night	43% 9% 12% 18% 16% 2	2794
	11th to 20th	Night	38% 10% 12% 26% 12% 1	2507
	21st to end	Night	35% 10% 13% 18% 20% 4	2751
June	1st to 10th	Night	31% 9% 14% 24% 19% 2	1520
	11th to 20th	Night	33% 7% 11% 23% 23% 3	1520
	21st to end	Night	37% 7% 14% 21% 19% 2	1520
July	1st to 10th	Night	43% 7% 15% 20% 12% 3	2490
	11th to 20th	Night	25% 7% 16% 33% 18% 1	2482
	21st to end	Night	33% 9% 15% 20% 21% 3	2662
August	1st to 10th	Night	29% 7% 15% 29% 19% 2	2557
	11th to 20th	Night	30% 8% 14% 30% 17%	3120
	21st to end	Night	29% 7% 13% 30% 18% 3	3476
September	1st to 10th	Night	31% 6% 11% 26% 24% 3	1900
	11th to 20th	Night	30% 6% 10% 31% 21% 3	1966
	21st to end	Night	35% 7% 10% 29% 18% 1	2090
October	1st to 10th	Night	24% 4 7% 36% 28% 1	3665
	11th to 20th	Night	34% 4 9% 26% 24% 3	3779
	21st to end	Night	42% 5% 9% 25% 16% 3	4436
November	1st to 10th	Night	38% 6% 9% 27% 18% 3	2536
	11th to 20th	Night	49% 5% 13% 21% 12% 1	2600
	21st to end	Night	51% 5% 11% 22% 10% 1	2745
December	1st to 10th	Night	53% 5% 12% 20% 8% 1	2779
	11th to 20th	Night	54% 6% 13% 19% 8% 1	3281
	21st to end	Night	67% 7% 10% 12% 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	19% 14% 33% 25% 9%	270
	11th to 20th	Day	20% 14% 40% 22% 3 1	270
	21st to end	Day	22% 11% 36% 26% 4 1	297
February	1st to 10th	Day	17% 18% 39% 18% 7%	270
	11th to 20th	Day	19% 21% 33% 23% 4	270
	21st to end	Day	22% 19% 40% 16% 3	225
March	1st to 10th	Day	16% 22% 40% 16% 5%	270
	11th to 20th	Day	23% 19% 35% 14% 8% 1	270
	21st to end	Day	28% 15% 30% 19% 7% 2	496
April	1st to 10th	Day	26% 14% 33% 22% 5%	460
	11th to 20th	Day	22% 21% 26% 19% 9% 3	452
	21st to end	Day	23% 15% 29% 22% 10% 1	460
May	1st to 10th	Day	18% 17% 31% 23% 9% 2	481
	11th to 20th	Day	22% 10% 30% 23% 12% 3	675
	21st to end	Day	17% 10% 27% 24% 16% 6%	734
June	1st to 10th	Day	10% 8% 31% 29% 18% 5%	680
	11th to 20th	Day	13% 5% 34% 29% 15% 5%	680
	21st to end	Day	12% 8% 28% 32% 15% 4	680
July	1st to 10th	Day	9% 3 19% 31% 25% 13%	671
	11th to 20th	Day	9% 4 26% 31% 21% 9%	668
	21st to end	Day	7% 3 24% 36% 22% 8%	739
August	1st to 10th	Day	9% 4 19% 33% 25% 11%	676
	11th to 20th	Day	11% 5% 18% 28% 23% 16%	488
	21st to end	Day	11% 5% 16% 31% 28% 10%	539
September	1st to 10th	Day	14% 7% 22% 27% 23% 7%	490
	11th to 20th	Day	11% 2 21% 30% 23% 13%	490
	21st to end	Day	14% 10% 28% 24% 16% 7%	490
October	1st to 10th	Day	15% 9% 29% 25% 17% 4	381
	11th to 20th	Day	22% 19% 31% 19% 8%	300
	21st to end	Day	30% 15% 28% 22% 5%	330
November	1st to 10th	Day	17% 16% 36% 20% 9% 2	300
	11th to 20th	Day	20% 17% 40% 15% 7% 1	300
	21st to end	Day	25% 12% 40% 18% 5%	300
December	1st to 10th	Day	16% 18% 43% 16% 6% 1	294
	11th to 20th	Day	18% 13% 37% 24% 8%	270
	21st to end	Day	26% 18% 38% 16% 2	297
January	1st to 10th	Night	19% 13% 37% 26% 6%	950
	11th to 20th	Night	22% 13% 37% 23% 5% 1	950
	21st to end	Night	20% 11% 36% 27% 6%	1045
February	1st to 10th	Night	21% 10% 40% 24% 5%	950
	11th to 20th	Night	18% 14% 37% 26% 5%	763
	21st to end	Night	23% 13% 38% 21% 4	628
March	1st to 10th	Night	21% 12% 36% 25% 6%	760
	11th to 20th	Night	15% 12% 36% 30% 7%	690
	21st to end	Night	24% 12% 31% 26% 6% 1	627
April	1st to 10th	Night	22% 13% 36% 24% 5%	570
	11th to 20th	Night	23% 13% 31% 26% 7%	563
	21st to end	Night	21% 9% 35% 27% 8% 1	570
May	1st to 10th	Night	18% 9% 35% 30% 7% 1	570
	11th to 20th	Night	17% 6% 33% 33% 11%	561
	21st to end	Night	15% 4 30% 35% 16%	617
June	1st to 10th	Night	8% 5% 29% 44% 14% 1	570
	11th to 20th	Night	12% 5% 31% 40% 11% 1	570
	21st to end	Night	10% 5% 29% 39% 17% 1	570
July	1st to 10th	Night	8% 2 17% 41% 28% 4	555
	11th to 20th	Night	7% 4 21% 43% 24% 1	552
	21st to end	Night	7% 2 19% 46% 24% 2	624
August	1st to 10th	Night	6% 2 16% 46% 28% 4	567
	11th to 20th	Night	8% 4 13% 40% 31% 5%	564
	21st to end	Night	10% 2 16% 41% 28% 4	627
September	1st to 10th	Night	9% 4 21% 37% 25% 4	570
	11th to 20th	Night	12% 4 20% 34% 26% 4	636
	21st to end	Night	12% 8% 27% 32% 20% 2	760
October	1st to 10th	Night	14% 5% 32% 32% 15% 1	760
	11th to 20th	Night	22% 11% 30% 26% 10%	760
	21st to end	Night	23% 11% 33% 25% 7%	836
November	1st to 10th	Night	17% 11% 37% 24% 10% 1	780
	11th to 20th	Night	20% 16% 35% 23% 6%	800
	21st to end	Night	21% 12% 36% 24% 6%	945
December	1st to 10th	Night	22% 11% 39% 22% 6%	993
	11th to 20th	Night	23% 11% 35% 26% 5% 1	950
	21st to end	Night	29% 13% 34% 22% 2	1045

Page generated at 2024-12-06 02:54:50. Version ac07

Copyright © 2024 Attilla Danko.