HoneyHQ

Climate, weather and honey

Honey harvests swing wildly between years, and they always have. Separating a bad season from a changing climate is the whole difficulty, and most writing on the subject does not attempt it.

History and cultureReviewed 2026-10-31

Four things that are not the same

The distinctions this subject depends on. Collapsing them is the commonest error in writing about bees and climate, in both directions.
LevelTimescaleWhat it explainsWhat it cannot explain
WeatherDays to a seasonWhy this year's crop failed: a wet June, a late frost, drought at the wrong momentAnything about direction over decades
Climate trendDecadesShifts in average flowering date, growing-season length, range boundariesAny individual season, which is dominated by weather
Extreme eventDaysA single catastrophic loss — heat dome, flood, unseasonal freezeWhether the event was made likelier, without attribution analysis
Local variabilityAnyWhy one valley cropped and the next did not: aspect, altitude, soil, land useRegional or global patterns

A beekeeper's experience is almost entirely of the first and fourth. That is not a failure of observation — it is what a single apiary can see. It is also why beekeeper reports, which are genuinely valuable, cannot on their own establish a trend.

What actually determines a honey crop

Nectar is secreted by plants under conditions that are narrower than people expect. Temperature, soil moisture, humidity and time of day all affect secretion, and the plant has to be flowering, and the bees have to be able to fly. Any of those failing removes the crop.

  • Drought reduces nectar secretion, and severe drought can stop it — a plant short of water does not spend it on nectar.
  • Rain during bloom keeps bees in and can wash nectar from open flowers. A wet fortnight at the wrong moment loses a whole flow.
  • Heat can shorten bloom, and extreme heat can abort it. Warmth is good for foraging and bad for a bloom that finishes in a week rather than three.
  • Frost after bud break destroys the flowers before they open, which is why a mild winter followed by a cold snap is worse than a steady cold one.
  • Wind suppresses foraging and dries nectar in the flower.

Honeydew honeys add a further dependency: they need the sap-feeding insects that produce the honeydew, whose populations swing on their own weather-driven cycles. Honeydew flows are famously unreliable for exactly this reason.

Where the climate evidence is stronger and weaker

Phenological shift is the best-supported part. Long-run records in several temperate regions show flowering occurring earlier on average, and growing seasons lengthening. That is a trend measured over decades and it is not seriously disputed.

What follows for bees is far less settled. The phenological mismatch hypothesis — that plants and pollinators shift at different rates and fall out of step — is plausible, actively researched, and not established as a general phenomenon. Results differ by species and by region, and honey bees are generalists with a long active season, which makes them less exposed to mismatch than a specialist solitary bee emerging for one plant.

What beekeepers are actually adapting to

Reported adaptations are mostly about timing and unpredictability rather than about a directional loss: earlier springs shifting when colonies need space, longer autumns extending the season during which colonies consume stores, milder winters allowing brood rearing to continue when a clean break would be better, and greater year-to-year variance making planning harder.

Variance is the underrated part. A beekeeper can adapt to a season that is reliably two weeks earlier. Adapting to a season that might be two weeks earlier or three weeks later is a different problem, and it is the one most often described.

Drought and heat, from the flower to the colony

Drought reaches bees through flowers before it reaches them any other way. Under rain shelters on British chalk grassland, every experimental plant community lost floral units, two lost species richness, and two of three wildflowers studied had a smaller share of flowers containing nectar. In growth chambers, borage under water stress and a 6 °C rise made about 0.8 µl of nectar per flower instead of about 6.1, while heat alone halved its pollen per flower but raised the pollen's protein concentration. These are the plant's responses, and they differ between species: one plant's loss is not a forecast for another's.

The colony has its own defences. When the nest overheats, workers collect more water and spread it for evaporative cooling, and colonies hold the brood nest within about 32–36 °C; brood kept too long below 32 °C develops with shrivelled wings and legs. That is colony regulation, which depends on water within reach — a different thing from any one bee's heat tolerance, which in one city's wild bees predicted which species declined with urban warming.

Drought

  1. Flowers and forage

    Field experiment: Simulated drought under rain shelters reduced the floral units of every experimental grassland community and the floral species richness of two.

    Plants under controlled conditions: In borage grown with soil humidity below 15%, nectar volume per flower fell, and under water stress combined with a 6 °C rise it fell from about 6.1 to 0.8 µl — some 60% less nectar sugar per flower.

  2. The individual bee

    Not established in the sources read

  3. The honey bee colony

    Not established in the sources read

  4. Wild bees

    Not established in the sources read

  5. Pollination

    Not established in the sources read

  6. The honey crop

    Not established in the sources read

Insecticides

  1. Flowers and forage

    Not established in the sources read

  2. The individual bee

    Field experiment: Foragers given a non-lethal dose of thiamethoxam and released away from the hive failed to return home more often than undosed foragers.

  3. The honey bee colony

    Field experiment: In the same Swedish landscape experiment, honey bee colonies showed no significant response to the treated crop.

    Field experiment: On commercial oilseed rape in Hungary, Germany and the United Kingdom, neonicotinoid seed treatments had negative effects on honey bees in Hungary and the UK and positive ones in Germany during flowering; in Hungary colonies were 24% smaller the next spring.

  4. Wild bees

    Field experiment: In replicated, matched Swedish landscapes, oilseed rape grown from seed coated with clothianidin and the pyrethroid β-cyfluthrin was associated with lower wild bee density, less solitary bee nesting, and reduced bumblebee colony growth and reproduction.

  5. Pollination

    Not established in the sources read

  6. The honey crop

    Not established in the sources read

Apiary density

  1. Flowers and forage

    Field experiment: On the 2.6 km² island of Giannutri, closing the island's 18 hives for 11 hours a day at the peak of wild bee foraging raised nectar volume by about 60% and pollen availability by about 30% in the most-visited plants.

  2. The individual bee

    Not established in the sources read

  3. The honey bee colony

    Not established in the sources read

  4. Wild bees

    Field experiment: With the hives closed, Anthophora dispar and Bombus terrestris became dominant in the island's visitation network and foraged more intensively.

    Field observation: In rosemary scrubland in southern France, high-density beekeeping was associated with 55% lower wild bee occurrence and 50% lower wild bee nectar foraging success within 600–1,100 m of apiaries — and with lower nectar and pollen harvest by the honey bees themselves.

    Field observation: In Paris, visits by wild pollinators fell as honey bee colony density within 500 m and 1,000 m rose; in Montréal, after an influx of almost 3,000 colonies, wild bee richness and pollen availability were negatively related to honey bee abundance, most strongly for small bees.

    Review or meta-analysis: Of studies examining competition between managed and wild bees reviewed in 2017, 53% reported negative effects on wild bees, 28% no effect and 19% mixed effects; a 2022 update with the same search terms found 47% more papers and considerable new evidence on competition.

  5. Pollination

    Not established in the sources read

  6. The honey crop

    Not established in the sources read

Three factors traced from the flowers to the honey crop, one level at a time. Each filled step is a recorded finding with the setting it was observed in; an empty step is a level the sources read do not reach, which is not the same as no effect. The chain is rarely complete: most evidence stops at the flower or the individual bee. Sources: Drought reduces floral resources for pollinators; Climate change-induced stress reduce quantity and alter composition of nectar and pollen from a bee-pollinated species (Borago officinalis, Boraginaceae); A common pesticide decreases foraging success and survival in honey bees; Comment on 'A common pesticide decreases foraging success and survival in honey bees'; Seed coating with a neonicotinoid insecticide negatively affects wild bees; Country-specific effects of neonicotinoid pesticides on honey bees and wild bees; Island-wide removal of honeybees reveals exploitative trophic competition with strongly declining wild bee populations; Controlling the impact of the managed honeybee on wild bees in protected areas; Wild pollinator activity negatively related to honey bee colony densities in urban context; Decline in wild bee species richness associated with honey bee (Apis mellifera L.) abundance in an urban ecosystem; Do managed bees have negative effects on wild bees? A systematic review of the literature; Mounting evidence that managed and introduced bees have negative impacts on wild bees: an updated review. Drawing: HoneyHQ (HEKNO Ltd), original.

Timing matters as much as amount. Over 130 years, ten generalist wild bee species in north-eastern North America advanced their spring emergence by about 10 days, at a pace not distinguishable from the plants they visit — evidence against a general mismatch for those bees, not proof that every species keeps pace. Gaps are local: on farms in south-west England nectar peaked in May and July, with a 'June gap' between and shortages in March and late summer; in French farmland, colonies collected heavily during the oilseed rape and sunflower blooms and little in the two months between.

Drought, heat and the forage calendar: what was found, and where
FactorLevelWhat was foundEvidenceWhat it does not show
DroughtFlowers and forageSimulated drought under rain shelters reduced the floral units of every experimental grassland community and the floral species richness of two. Meadow vetchling and selfheal had a smaller share of flowers containing nectar; sainfoin had fewer flowers per raceme.Field experiment (experiment) — Lathyrus pratensis, Prunella vulgaris, Onobrychis viciifolia; Calcareous grassland plots, United KingdomFlowers were measured, not bees: no visits, colony stores or honey yields were recorded. Plant functional diversity did not buffer the loss in this trial, and other species and soils may respond differently.
DroughtFlowers and forageIn borage grown with soil humidity below 15%, nectar volume per flower fell, and under water stress combined with a 6 °C rise it fell from about 6.1 to 0.8 µl — some 60% less nectar sugar per flower. The amino-acid make-up of the nectar changed too.Plants under controlled conditions (experiment) — Borago officinalis; Growth chambersOne species under controlled conditions. It shows that a drought can cut nectar per flower, not how much any field crop or meadow loses, and nothing about bees was measured.
HeatFlowers and forageRaising growth temperature by 3 and 6 °C halved borage pollen weight per flower while raising its polypeptide concentration by about 65%; water stress alone did not change pollen weight.Plants under controlled conditions (experiment) — Borago officinalis; Growth chambersLess pollen with more protein per gram is a change in composition, not a simple loss, and what it means for a bee's diet was not tested.
HeatThe honey bee colonyWhen the nest overheats, a honey bee colony increases its collection of water, which workers spread in the nest for evaporative cooling.Field experiment (experiment) — Apis mellifera; Experimental coloniesDescribes the colony's response, not a temperature at which it fails. A colony's thermoregulation is separate from any single bee's heat tolerance, and it depends on water being within reach.
HeatThe honey bee colonyColonies hold the brood nest within about 32–36 °C; brood kept too long below 32 °C develops with shrivelled wings and legs.Review or meta-analysis (synthesis) — Apis mellifera; Review of temperate colony studiesThe band is the colony's target, maintained by worker heating and cooling; it says nothing about how often real weather pushes a colony outside it.
HeatWild beesAcross 18 urban sites in Raleigh, North Carolina, the heat tolerance (critical thermal maximum, 44.6–51.3 °C) of 15 wild bee species predicted how their populations responded to urban warming; species with the lowest tolerance declined most.Field observation (correlation) — 15 wild bee species; Raleigh, North Carolina, United StatesA correlation in one city's bee community. It is consistent with heat limiting some species there; it does not by itself establish heat as the mechanism, nor predict other cities.
Shifts in flowering and emergenceWild beesOver 130 years the spring emergence of ten generalist wild bee species in north-eastern North America advanced by a mean of about 10 days, mostly since 1970; estimated advances in the plants they visit were not distinguishable from the bees'.Field observation (correlation) — 10 generalist wild bee species; North-eastern North America (museum records)No general mismatch was found for these bees and their plants; that is not evidence that specialists, other regions or crops keep pace. A shared advance is associated with warming, which the records cannot isolate as the only factor.
Gaps in forageFlowers and forageWhole-farm nectar supply on farms in south-west England peaked in May and July, with a 'June gap' between, and was low in March and in August–September, when it was unlikely to meet bumblebee demand.Field observation (correlation) — Farmland flowering plants, Bombus spp. (demand estimated); Farms in south-west EnglandA regional calendar. The months of a gap depend on the plants, farming and weather of a place; this is not a calendar for elsewhere.
Mass-flowering cropsThe honey bee colonyIn French intensive farmland, five years of collection by honey bee colonies were bimodal: high during the oilseed rape and sunflower blooms, with a two-month low between them. Nectar came mainly from the crops; pollen from many wild and woody species.Field observation (correlation) — Apis mellifera; Intensive farmland, western FranceDescribes what colonies collected, not their health. A mass-flowering crop supplies a great deal briefly; whether the low period between blooms harms colonies was not the measure.

Every row belongs to its species and place; none is a forecast for another region. No finding is recorded here at the level of: the individual bee, pollination, the honey crop — not established in the sources read, which is not the same as no effect.

Checked 2026-10-31 against: Drought reduces floral resources for pollinators (Global Change Biology 24(7):3226–3235 (Phillips, Shaw, Holland and colleagues), 2018); Climate change-induced stress reduce quantity and alter composition of nectar and pollen from a bee-pollinated species (Borago officinalis, Boraginaceae) (Frontiers in Plant Science 12:755843 (Descamps, Quinet and Jacquemart), 2021); The control of water collection in honey bee colonies (Behavioral Ecology and Sociobiology 41:407–422 (Kühnholz and Seeley), 1997); Honeybee colony thermoregulation – regulatory mechanisms and contribution of individuals in dependence on age, location and thermal stress (PLoS ONE, 2010); Physiological thermal limits predict differential responses of bees to urban heat-island effects (Biology Letters, 2017); Climate-associated phenological advances in bee pollinators and bee-pollinated plants (Proceedings of the National Academy of Sciences 108(51):20645–20649 (Bartomeus and colleagues), 2011); Phenology of farmland floral resources reveals seasonal gaps in nectar availability for bumblebees (Journal of Applied Ecology 56(7):1585–1596 (Timberlake, Vaughan and Memmott), 2019); Honey bee diet in intensive farmland habitats reveals an unexpectedly high flower richness and a major role of weeds (Ecological Applications 25(4):881–890 (Requier and colleagues), 2015).

The claims on this page

Every substantive claim is placed on a tier, and the top two tiers must also state what they are not claiming.

Emerging research

Real studies exist and point somewhere, but they are small, in vitro, in animals, or not yet replicated. Direction is not the same as a result.

Emerging research

Flowering has on average shifted earlier in several temperate regions over recent decades.

Long-run phenological records show earlier average flowering and longer growing seasons in a number of temperate regions. Magnitude and direction vary by species, elevation and latitude.

What this does not claim: That plants and pollinators have demonstrably fallen out of step. Phenological mismatch is an active hypothesis with mixed results, not an established general phenomenon — and generalist honey bees are less exposed to it than specialist solitary bees.

Commonly claimed, but not supported

Widely repeated and not supported by current evidence. Listed so the correction is here rather than only the claim.

Commonly claimed, but not supported

A poor honey harvest in a given year can be attributed to climate change.

Individual seasons are dominated by weather and local conditions. Attributing a specific harvest, bloom failure or colony loss to climate change requires trend analysis or formal attribution work, not the observation that the season was bad.

What this does not claim: That climate has no effect on honey production. Phenological shift is well evidenced over decades; the point is that a decade-scale trend does not explain a single year.

Sources

  • Drought reduces floral resources for pollinators — Global Change Biology 24(7):3226–3235 (Phillips, Shaw, Holland and colleagues) (2018) · Peer-reviewed article Link
  • Climate change-induced stress reduce quantity and alter composition of nectar and pollen from a bee-pollinated species (Borago officinalis, Boraginaceae) — Frontiers in Plant Science 12:755843 (Descamps, Quinet and Jacquemart) (2021) · Peer-reviewed article Link
  • The control of water collection in honey bee colonies — Behavioral Ecology and Sociobiology 41:407–422 (Kühnholz and Seeley) (1997) · Peer-reviewed article Link
  • Honeybee colony thermoregulation – regulatory mechanisms and contribution of individuals in dependence on age, location and thermal stress — PLoS ONE (2010) · Peer-reviewed article Link
  • Physiological thermal limits predict differential responses of bees to urban heat-island effects — Biology Letters (2017) · Observational study Link
  • Climate-associated phenological advances in bee pollinators and bee-pollinated plants — Proceedings of the National Academy of Sciences 108(51):20645–20649 (Bartomeus and colleagues) (2011) · Peer-reviewed article Link
  • Phenology of farmland floral resources reveals seasonal gaps in nectar availability for bumblebees — Journal of Applied Ecology 56(7):1585–1596 (Timberlake, Vaughan and Memmott) (2019) · Peer-reviewed article Link
  • Honey bee diet in intensive farmland habitats reveals an unexpectedly high flower richness and a major role of weeds — Ecological Applications 25(4):881–890 (Requier and colleagues) (2015) · Peer-reviewed article Link
  • Assessment Report on Pollinators, Pollination and Food Production — Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) (2016) · Systematic review Link
  • HoneyHQ editorial synthesis — HEKNO Ltd · HoneyHQ synthesis
  • The Lives of Bees: The Untold Story of the Honey Bee in the Wild — Princeton University Press (2019) · Monograph

How sources are selected and weighted is set out in the sources and evidence policy.

Documented traditions

Specific practices behind this subject, each naming where it is documented, among whom, and whether anyone still does it.

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